Section IV: 1980’s – 2017 (Leaders, Inventions, and Technology Pioneers)
The Labs and Centers described above have been key to the generation of new technology through the dedicated efforts of faculty and students working in collaboration toward a common goal. Most were made possible through government programs.
Following is a description of the impact of that sponsored research in several major areas.
MEMS and Integrated Microsystems
Microelectromechanical systems (MEMS), composed of tiny sensors, actuators, and micromachines, have tremendous marketplace potential. They are used for precise sensing of the environment, for monitoring infrastructure integrity, and for both diagnosing and treating a variety of health issues. They control the cars we drive and the airplanes we fly. Ranging from a few millionths to several thousandths of a meter in size, MEMS devices are often combined on a single chip with microelectronic circuits to become complete microsystems. They are key elements in today’s smartphones.
When Ken Wise joined the University in 1974, he set about turning Michigan into a world leader in the development of integrated sensors, microelectromechanical systems (MEMS), and microsystems.
MEMS was coalescing as a distinct discipline in the early 80’s, marked by newly-formed conferences in the field. Prof. Wise and his colleagues were heavy players early on in the Transducers conference, which was initiated in 1981, and he was instrumental in establishing the Solid-State Sensors, Actuators and Microsystems Workshop (Hilton Head Conference), first held in 1984. When DARPA formed its MEMS activities in the early 1990’s, one of the first programs funded was a project proposed by Prof. Wise and his former student-turned-colleague, Khalil Najafi.
Following is a summary of key technology that established Michigan’s reputation in MEMS and Integrated Microsystems. The specific achievements in sensor technology and neural probes are discussed separately because of the impact of that effort. They could easily have been incorporated into the history of MEMS and Microsystems:
- 1980, the first silicon micromachined uncooled infrared detector. This technology is now found in commercial products, such as appliances, security systems, ear thermometers, and radiometry.
- 1985, development of an uncooled thermopile imaging array with on-chip electronics – later commercialized.
- 1986, developed the dissolved-wafer-silicon-on-glass process
- 1988, the first conductivity-based “microhotplate” gas detectors
- 1989, Pioneering research on high-resolution tactile and infrared imagers
- 1989, pioneering work on thermal- and pressure-based flowmeters
- 1989, the first university program in hermetic wafer-level packaging
- 1990, CMOS microflowmeter containing sensors for pressure, temperature, gas type, flow rate, and flow direction with readout electronics was the first of its kind
- 1994, Michigan reported the first integrated ring gyroscope for use in inertial sensors. The basic device was commercialized by GM/Delco and was the highest performing automotive gyroscope of its time. Gyroscopes and accelerometers detect rotation, and are used for navigation, such as in GPS devices.
- 1994, Breakthroughs in hermetic packaging and in RF-based telemetry interfaces for implantable microsystems.
- 1997, a 50cc Michigan/CISC microinstrumentation cluster flew on an unmanned aerial vehicle, up-linking data to a satellite. It was the first wireless integrated microsystem developed at Michigan, and pioneered sensor bus interfaces, sensor-circuit integration, power management, and micropower sensors for barometric pressure, temperature, humidity, shock, and vibration.
Najafi remains a world leader in this area, and is currently working on technology that will enable navigation using micromachined inertial sensors in instances when GPS fails or is not available.
- 1998, the world’s first successful electronic readouts from monolithic DNA analysis chips
- 1998, the first tactical-grade ring gyro along with accelerometers capable of 5µg resolution. Prof. Najafi’s accelerometers are among the very best ever reported, and are now moving below 1mg in resolution.
- 1999, the first fully integrated electrical stimulation chip with on-chip coils and a BiCMOS integrated circuit. This was part of a variety of circuits developed for wireless operation of implantable microsystems, and the first to demonstrate a wireless bi-directional system for operation of sensors inside biological tissue.
- 2004, first reported pressure/flow-sensing microsystem for use in an arterial stent.
- 2013, the smallest reported inertial system, measuring 13 cubic millimeters, and containing a clock and six sensors that detect movement along six different axes.
Micropackaging is a major and fundamental challenge in microsystems technology. Sensors must be protected from the environment, yet still able to sense the environment and communicate with it in some way. Packaging has become the most expensive aspect of manufacturing for miniature sensors and computers. Prof. Najafi leads one of the most advanced groups in the world in the area of hermetic packaging of biological sensors, as well as accelerometers, micromechanical resonators, and pressure sensors.
In the last decade Prof. Najafi has turned his attention to miniature energy harvesters to address the disproportionate amount of space devoted to the batteries needed to power miniaturized sensing devices. He developed piezoelectric energy harvesters that turn vibrations into electricity. In 2011, his group built a millimeter-scale vibration energy harvester that powers wireless sensor networks better than any similar device on the market.
Prof. Wise has spent decades improving the state of the art of cochlear implants. In 2005, his group achieved a thin-film silicon-parylene array, which was the first of its kind. It was a major step to improving the frequency range and resolution in cochlear prostheses. In 2010, his group built the first cochlear implant array specially designed to achieve the stiffness and curl needed for deep insertion, setting the stage for an automated insertion process that will take cochlear implants to the limits set by physiology.
Prof. Wise became a member of the National Academy of Engineering in 1998, “For sensors and microelectromechanical systems.”
Sensors, Neural Probes, and the Brain
Sensor research at Michigan was led by Prof. Ken Wise. One of his early projects was an esophageal catheter that he developed with Dr. Mark Orringer in the Medical School. He marveled that as an assistant professor he was able to collaborate with a brilliant surgeon who would become one of the top thoracic surgeons in the country.
In the following decades, Prof. Wise and a team of colleagues established a world-class program in sensor research that quickly moved into neural probes. Beginning in 1994, the “Michigan probes” were being distributed worldwide, changing research directions in the neuro-sciences. Its history at that point was described above in the summary of the CNCT.
Here are a few of the major advances in the technology that allowed researchers to incorporate tech devices into the human body:
- 1976, the first known pressure sensor with on-chip readout circuitry. It was the first micromachined sensor developed at Michigan.
- 1982, the first practical probes for exploring the central nervous system at the cellular level were demonstrated
- 1982, SENSIM, one of the first sensor CAD programs, was developed to analyze performance of newly created silicon capacitive pressure sensors.
- 1984, the first capacitive pressure sensors with switched-capacitor charge readout
- 1985, the first neural probe integrated with on-chip readout circuitry
- 1985, world’s smallest catheter-based pressure sensor, a silicon-on-glass structure realized with the dissolved wafer process, capable of measuring blood pressure within the coronary arteries
- 1988, the first work on sensor bus standards, self-testing, and digital compensation
- 1991, the first integrated active neural stimulating array with iridium sites was realized at Michigan to advance neural prostheses.
- 1994, First bulk-micromachined neural probe that allowed in-vivo drug delivery at the cellular level along with electrical recording and stimulation. These multi-channel “Michigan probes” began to be distributed worldwide, changing research directions in the neuro-sciences
- 1997, first 3D CMOS probes for extracellular single-unit recording in the central nervous system.
- 2000, first high-density 3D neural probe array for exploring the organization of the central nervous system.
- 2001, barometric pressure sensors developed that were the first to integrate a closed-loop vacuum control system into their reference cavity, achieving 25mTorr accuracy.
- 2002: First neural probes containing on-chip CMOS circuitry to record activity in unrestrained animals (collaboration with Rutgers University).
- 2006: Thermal flowmeters are successfully integrated on the 40μm-wide shank of a neural probe for the first time to meter drug delivery at the cellular level.
- 2007: A wireless implantable electrode array was developed for capturing control signals from the motor cortex, fitting on a U.S. penny. It was the first such array ever realized.
- 2007 milestone: more than 7,500 Michigan Probes had been provided to investigators worldwide.
- 2008: First neural recording array to use deep reactive ion etching to realize high-yield 3D electrode arrays. These electronic interfaces to the nervous system are leading to prostheses for deafness, blindness, epilepsy, paralysis, and Parkinson’s Disease.
Prof. Euisik Yoon and Prof. Ken Wise are continuing to advance the state-of-the-art in neural probes by incorporating a relatively novel technique called optogenetics into their research. This is a technique in which individual neurons can be activated and de-activated through light, and is expected to help unravel the mysteries of how the brain works.
In research led by Yoon and Wise, neural probes were built and tested in mice that hold what are believed to be the smallest implantable LEDs ever made. The new probes can control and record the activity of many individual neurons, measuring how changes in the activity of a single neuron can affect its neighbors.
This groundbreaking tool combines LED’s on silicon probes that are as small as an individual human cell. The advances in knowledge and neural implant technology could lead to better prosthetics and treatments for conditions like Alzheimer’s, Parkinson’s disease, deafness, blindness, paralysis and depression.
Prof. Yoon and Prof. Wise also received a grant from NSF to cross-train an international group of neuroscientists and engineers in this area of research.
Sensing in the Terahertz Frequency
Terahertz rays are light waves that are too long for human eyes to see, yet also not detectable by specialized tools presently used to detect light. Profs. Guo and Norris have demonstrated a unique terahertz detector and imaging system that could bridge this terahertz gap. Potential applications range from the detection of chemical and other weapons, to safer imaging of body tissue, and even the study of planets in other solar systems.
Their technology converts the terahertz waves into ultrasound, which can then be detected by a highly sensitive acoustic sensor. The sound the detector makes is too high for human ears to hear. Their detector is compact and can operate at room temperature in real time.
Gas Chromatograph – Sensing chemicals
Michigan researchers (Ken Wise; and more recently Khalil Najafi and Yogesh Gianchandani) have been leaders in developing miniaturized gas chromatographs that can detect the presence of chemical agents quickly and accurately. These devices could revolutionize security, environmental monitoring, food processing, and health care by enabling low-cost, widely-deployable gas analysis.
Previous gas chromatographs were very large – and not portable. The Michigan devices fit in the palm of one’s hand, and are being designed to fit on autonomous aerial vehicles as part of the COMBAT project. Advances in this area of research include:
- 2004 – Deep silicon etching technology is used to realize the highest performance chromatographic separation microcolumns in the world.
- 2006 – A chromatographic separation system is realized in a structure a little larger than a dime, advancing miniature gas analysis systems.
- 2010 – First palm-size completely integrated gas chromatograph system ever implemented. Called Mercury, it included temperature control electronics, an embedded processor, and a USB interface.
- 2010 – Orion is a prototype gas analyzer that explores the fundamental limits of chromatography-based gas analysis systems in terms of power, speed, and size. Gas analyzers such as this allows for breath analysis to determine tuberculosis and lung cancer.
- 2013 – Prof. Yogesh Gianchandani and his group built three different types of record-breaking micro scale vacuum pumps that could greatly extend the capabilities of electronics and sensing devices that use these devices, such as gas analyzers for homeland security, healthcare, search and rescue, and other applications. Prof. Najafi and his group developed a penny-sized vacuum system that was initially designed to help detect chemical weapons. The device can be mass-produced at low cost, and integrated with a variety of consumer-based microelectronic devices for a variety of applications.
Lasers, Lighting, and Quantum Dot Devices
Prof. Pallab Bhattacharya was instrumental in establishing The University of Michigan as a premier institution in optoelectronics research. He has made fundamental contributions in the area of compound semiconductor materials, and used this knowledge to build novel and state-of-the-art optoelectronic and electronic devices.
Much of Bhattacharya’s groundbreaking research is founded on his discovery in 1988, with colleague Jasprit Singh, of a new technique for growing unique semiconductor structures, which came to be known as self-assembled quantum dots.
Quantum dots, first discovered in the early 1980’s, are the cornerstone of a broad spectrum of research at the nanoscale. A quantum dot is a 2-10 nanometer particle made of some semiconductor material. Like many nanoscale particles, they display unique characteristics from the same material in bulk – which make them a fascinating source for new technologies, including lighting sources, lasers, solar cells, medical imaging, and quantum computing.
Following the discovery of self-organized quantum dots, Bhattacharya and colleagues at Michigan, namely Rachel Goldman (Materials Science and Engineering), Ted Norris, Brad Orr (Physics), and Jasprit Singh, illuminated the phenomenon through rigorous testing and further experimentation. Michigan was 7-10 years ahead of the research community in this area, and in the coming decades Bhattacharya developed numerous novel devices based on quantum dots.
Prof. Bhattacharya and others (Jasprit Singh, Jamie Phillips – a graduate student at the time, and Ted Norris), were among the first to report room temperature operation of a quantum dot laser in 1996. Subsequent research established the quantum dot laser as the best semiconductor laser available in terms of performance characteristics.
Virtually all contemporary high-performance photoreceivers use the integration technique pioneered by Bhattacharya and his co-workers in the mid 1990’s. These photoreceivers are used in industry today as optical fiber communication links.
More recently, Prof. Bhattacharya has made dramatic advancements in quantum dot lasers that will eventually find applications in solid-state lighting, full color mobile projectors, optical data storage, and even medical and military applications.
In 2011, Bhattacharya demonstrated 524-nanometer (nm) green and 480-nm blue quantum dot lasers with better efficiency than equivalent quantum well lasers. His 630-nm red quantum dot laser has achieved the longest ever emission wavelength using nitride materials. A potential major application of red emitting lasers is heads-up displays in automobile windshields.
In 2013, Prof. Bhattacharya and a small team of researchers created a near-equilibrium room temperature Bose-Einstein condensate, a scientific milestone that opens up entirely new avenues of research and is expected to lead to increasingly sensitive instrumentation and measurements.
Prof. Bhattacharya developed the first electrically injected polariton laser in 2012 (using inorganic material), a feat that researchers around the world had been trying to demonstrate since it was first proposed in 1996. The research was published in 2013. This laser takes about 1,000 times less energy to operate than a conventional laser, and can be potentially used in any application where a laser is used today, such as consumer electronics, optical communications and the Internet, laser surgery and other medical applications, and displays.
In 2014, Bhattacharya reported the first room-temperature polariton laser that is fueled by electrical current as opposed to light. Being able to operate the device at room temperature is key to incorporating the technology into practical electronics. This breakthrough could advance efforts to replace on-chip wire connections with lasers, leading to smaller and more powerful electronics.
In 2008, Prof. Bhattacharya was elected to the National Academy of Engineering for his contributions to quantum-dot optoelectronic devices and integrated optoelectronics.
Several faculty are conducting research into new materials and processes to improve the efficiency of photovoltaic cells, more commonly known as solar cells. Stephen Forrest (MSE PHD Physics 1974 ‘79), Peter A. Franken Distinguished University Professor and Paul G. Goebel Professor of Engineering, has been a leader in this area for decades, long before he came to Michigan in 2006 as the Vice President for Research, and faculty member in EECS. He was elected to the National Academy of Engineering in 2003 for advances in optoelectronic devices, detectors for fiber optics, and efficient organic LEDs for displays.
In 2010, along with researchers at Argonne National Laboratory and Northwestern University, Forrest came up with a general theory for organics that was a theoretical corollary to Shockley’s well-known diode equation for semiconductors.
In recent work, Prof. Forrest and his team put this theory to the test, and it worked. His group achieved better than a 50% improvement in energy-conversion efficiency by developing techniques to control nanocrystalline order at the active interface in organic photovoltaics. This critical advance provides a fundamental understanding of the process of solar-to-electrical energy conversion in organic thin film solar cells, and the linkage of efficiency to molecular and crystal structure.
Prof. Forrest also discovered a way to build flexible solar cells made from the inorganic material gallium arsenide (GaAs) in a way that opens the door to mass production, which would dramatically lower their cost. He has shown 22% overall efficiency in these solar cells, and is investigating ways to increase that efficiency to 30%. This would put solar cells made from GaAs on a par economically with those made from silicon.
Prof. Jay Guo has designed and fabricated what are believed to be the first semi-transparent, colored photovoltaics. Unlike other color solar cells, Guo’s devices don’t rely on dyes or microstructures that can blur the image behind them. The cells are mechanically structured to transmit certain light wavelengths. With this technology, solar panels can be visually attractive, distinctive, and deployable in a wide variety of locations, such as on the on the sides of buildings, as energy-harvesting billboards and as window shades. They could be especially useful in densely populated cities.
Displays and Lighting
An organic light emitting diode (OLED) is an LED that contains an organic semiconductor, such as carbon. Unlike LED’s, they can be molded into any shape. OLED technologies, a nearly $16B market, are already found in more than 750 million smartphone and tablet screens worldwide.
The first modern OLED was developed by researchers at Eastman Kodak in 1987, but it was highly inefficient. The OLED industry began to really take off when Prof. Forrest built the first phosphorescent OLED with Prof. Mark E. Thompson (Dept. of Chemistry, USC) in 1998. Soon after, they were considered the hot new material for displays. When Samsung developed their super-sharp OLED displays for use in their Galaxy 3 and 4 smart phones, they used many of the same materials and device structures first developed in Prof. Forrest’s lab.
OLEDs may one day be used for general lighting, but compared to traditional LED’s, they lag in overall performance in terms of efficiency, longevity, and cost. Prof. Forrest and his group are working to overcome these deficiencies. They developed a microlens array technology to double the efficiency of OLED devices back in the early 2000s, reaching 40% in external quantum efficiency (EQE). In 2015, his team increased that 50% further by redirecting light that was previously lost in the OLED light emitting region itself.
OLEDs allow television screens to be extremely thin and even curved, with little blurring of moving objects and a wider range of viewing angles. But – the color blue has been a tough hurdle to overcome as this pixel color degrades quickly and is highly inefficient.
Forrest and his colleagues demonstrated the first phosphorescent OLED (PHOLED) in 1998 and the first blue PHOLED in 2001. In 2014, he was able to extend the lifetime of a blue POLED by ten times. In 2015, in collaboration with researchers at the University of Southern California, Forrest achieved a bright, deep blue at an efficiency and brightness that is close to meeting the stringent brightness requirements of the National Television Systems Committee.
In other lighting research and applications, Prof. P.C. Ku is is concerned about the quality of light available to individuals in closed office environments. Prof. Ku’s ideal office light will combine the blue light of the sun with bright, attractive, energy-efficient lighting. To achieve this goal, he’s working with Prof. Mojtaba Nawab (Architecture & Urban Planning) and Prof. Kwoon Wong (Ophthalmology & Visual Sciences) to find the right combination of lighting to satisfy both our conscious and subconscious vision. Prof. Ku formed a company with Prof. Max Shtein (Materials Science and Engineering) called Arborlight, which specializes in LED lighting for retail and office settings.
Computers and the VLSI Revolution
The education of modern computer hardware and design at Michigan can be traced back to Prof. Ron Lomax. Prof. Lomax recalled, “We were still teaching about vacuum tubes in 1961 when I first started at U-M. Transistors only came later. U-M had a big IBM mainframe using the MAD [Michigan Algorithm Decoder] operating system.” MAD was a programming language and compiler developed in 1959 by Bernard Galler, Bruce Arden, and Robert Graham.
Lee Boysel (BSE MSE EE ’62 ’63) was educated in this system. He said he graduated with a solid background in vacuum tube circuit and logic design, and a desire to start his own electronics firm. By 1968, he had founded Four Phase Systems, Inc. This company came out with the AL1 in 1969, which included all the basic elements of the modern microprocessor, a fact upheld in court after 10 years of litigation. Intel announced its first microprocessor in 1971. [more about Lee Boysel]
Much has been written about the revolution in computer chip design that occurred through the efforts of Lynn Conway and Carver Mead, neither associated with Michigan at the time. They had a vision to separate chip design from technology, so that even students could design a computer chip. They came out with the landmark text, Introduction to VLSI System Design, published in 1979, which transformed the education of VLSI design in the country.
Prof. Lomax attended Conway’s workshop at MIT in 1979, and began teaching VLSI in 1980. The advent of automated design was quickly followed by Conway’s promise to get industry to fabricate the student’s design. The combination of automated design and fabrication accelerated what students could learn in a university setting by a quantum leap.
Prof. Richard B. Brown joined Michigan in 1984, and took an important step in cementing Michigan’s reputation as a leader in VLSI and integrated circuits. Prof. Brown took the lead on VLSI chip design and fabrication, seeing that this is what the department needed at the time. He took over the advanced VLSI design course, which had been taught once before by Prof. John Hayes. Over the next several years, Prof. Brown continually revised the course, introducing current topics in VLSI and the latest CAD capabilities. EECS 627 became a major project class in which student teams designed microprocessors and other complex silicon chips.
A major improvement to student education in computer design came about when Prof. Brown sought to replace the fragmentary collection of software packages used in the Department with a consistent set of tools, which he accomplished by appealing directly to industry leaders. Through his efforts, the University of Michigan became a pioneer in the use of commercial CAD tools in academia.
Companies began to establish university programs which have benefited many other schools as well. All of the Department’s undergraduate circuit and computer courses were restructured to use this set of commercial design automation software running on engineering workstations.
Between 1985 and 2000, Michigan’s students participated in the Student VLSI Design Contest, a contest that originated in 1980 at the University of Utah. By the mid 1990’s, the contest was organized at Michigan and included the participation of industry as sponsors and judges. The contest merged with the Design Automation Conference (CAD) University Design Contest in 1999, soon after becoming the DAC/ISSCC Student Design Contest. In the first year of this contest (2000), there were 31 entries from 22 of the top universities throughout the world. U-M students took first prize in operational and both first and second prize in conceptual, as well as best paper. U-M continued to dominate in this contest, which ended in 2010.The tradition of industry-sponsored student design contests continues in courses such as Monolithic Amplifier Circuits (EECS 413), VLSI Design I (EECS 427), VLSI Design II (EECS 627), Image Processing (EECS 556), Integrated Analog/Digital Interface Circuits (EECS 511).In 2003, Intel identified Michigan as offering the model curriculum in VLSI curriculum. They funded Brown and several colleagues (including Prof. Dennis Sylvester, Prof. David Blaauw, and Prof. Michael Flynn) to document and disseminate the curriculum domestically and internationally.
As of 2017, Integrated Circuits and VLSI was one of the hottest single areas of interest among graduate students thanks to its current reputation and leadership of Profs. David Blaauw and Sylvester and other faculty of the Michigan Integrated Circuits Laboratory (MICL).
World’s Smallest Computer – The Michigan Micro Mote (M3)
Called the Michigan Micro Mote (M3), the world’s first millimeter-scale computer was achieved at Michigan in 2014 and began to be disseminated to researchers around the world. Its history reflects more than a decade of effort in low-power computing and miniature sensors. These devices are helping usher in the era of the Internet of Things (IoT), where people are connected to things and other people through the cloud. In the IoT world, size and power are everything. The computers have to be small in order to sense the world around us without being intrusive, and they have to run on extremely low power to match their size.
Some of the major breakthroughs that led to the Michigan Micro Mote include:
2008: Prof. Blaauw and Sylvester’s Phoenix processor set a record for low-power computing, consuming as little as 30 picowatts in standby mode (1pW is the average power consumption of a single human cell.). It was developed for use in an intraocular implant and intracranial pressure in trauma victims. The Phoenix processor measured only 915 x 915µm2.
2010: Prof. Blaauw and Sylvester’s group built the world’s first millimeter-scale (9mm3) solar-powered sensor system that can operate perpetually, called the Michigan Micro Mote (M3). It is 1,000x smaller than its nearest commercial counterpart. The microsystem included an ultra-low-power processor, energy-scavenging power system, and a wireless interface.
2014: With the addition of team members Prof. David Wentzloff and Prof. Prabal Dutta, who focused on wireless communication and software integration respectively, the M3 became a true computer, capable of taking in information, processing the data, and outputting the data. The Michigan Micro Mote contains solar cells that power the battery with ambient light, allowing the computers to run perpetually. It is constructed in layers that can be exchanged to serve different purposes. Their initial line of “smart dust” devices includes computers equipped with imagers (with motion detection), temperature sensors, and pressure sensors.
Worldwide exploration of this research is being aided by the dissemination of hundreds of Michigan Micro Motes for trials in innovative applications. In the meantime, the Michigan team continues to redefine computer technology ahead of the IoT curve as they collaborate with industry, the medical community, and colleagues here at Michigan and around the world.
Memristors for Nextgen Computer Memory, Image & Video Processing
Memristors offer the promise of transforming the semiconductor industry by enabling smaller, faster, cheaper chips and computers. In some areas, such as memory, the improvement over existing technology will be exponential. A memristor is a nanoscale computer component that offers both memory and logic functions in one simple package.
Prof. Wei Lu and his team built a specific type of memristor device called resistive random access memory (RRAM), which has fabulous inherent properties for computing. Prof. Wei Lu co-founded the company Crossbar, Inc., in order to commercialize the technology.
Because memristors combine high density with actions based on past behavior, Prof. Lu has been investigating whether they could work together in ways resembling human neurons. He is director of a new $5M project to build alternative computer hardware that could process images and video 1,000 times faster with 10,000 times less power than today’s systems—all without sacrificing accuracy. The project is titled Sparse Adaptive Local Learning for Sensing and Analytics. Other collaborators are ECE faculty Zhengya Zhang and Michael Flynn, Garrett Kenyon of the Los Alamos National Lab, and Christof Teuscher of Portland State University.
Graphene and Electronics
Graphene is a relatively new material that could bring on a revolution in the electronics world by competing with or even replacing silicon in high-performance computers and electronics. Graphene is comprised of a single layer of carbon atoms arranged in a hexagonal pattern. It is highly conductive, flexible yet harder than a diamond, and absorbs only 2.3% of the light it encounters. It is inexpensive, easily manufactured, and flexible.
Researchers around the world are investigating ways to exploit graphene. At Michigan, Prof. Ted Norris has been studying the ultrafast electron dynamics in this material since about 2007 to lay the groundwork for its use in practical devices.
Building on this information, Prof. Zhaohui Zhong and his team built the first known room temperature broadband infrared (IR) photodetector in 2014, thanks to graphene. IR detectors are used in a wide array of applications, including optical fiber communications and lasers; imaging in industry, medicine, and science; remote sensing; and detection of humans and animals during the day and night.
Zhong is also investigating graphene for next-generation flexible printed circuits, and has made great progress by developing the first all-graphene flexible, transparent digital modulator for high speed communications. Flexible printed circuits are used in many industries, including biomedical (devices that rest on the skin for health monitoring, as well as medical implants), energy (flexible solar cells), automotive systems, electronics (cell phones, displays, wearable electronics), and telecommunications.
Finally – in collaboration with Prof. Sherman Fan of Biomedical Engineering, Prof. Zhong’s group developed a new wearable graphene-based nanoelectronic vapor sensor that could one day offer continuous disease monitoring for patients with diabetes, high blood pressure, anemia or lung disease.
Signal Processing, Information Theory and Big Data
A signal is a piece of information. The more signals you have, the better chance there is to reconstruct the source of the signal. Information theory, machine learning, and big data are all focused on figuring out the meaning behind observed data.
Prof. Hero is a worldwide expert in statistical signal and image processing, machine learning, and data mining. His algorithms and theory have been applied to a wide array of areas, including: image processing; communication networks methods; intelligent vehicular systems; bioinformatics and biomedical data processing problems; and tomographic imaging algorithms for PET, SPECT, and MRI.
In recent work, he extended his theory to flow cytometry in order to better diagnose and classify various types of leukemia and lymphoma. Hero was awarded a U.S. patent in this work.
Al Hero is currently co-director of the Michigan Institute for Data Science (MIDAS). MIDAS is the focal point for the multidisciplinary discipline of data science at Michigan, and part of Michigan’s $100M Data Science Initiative. He has served as President of the IEEE Signal Processing Society and Director of Division IX (Signals and Applications). He co-authored the books, Foundations and Application of Sensor Management (2008) and Big Data over Networks (2016), and is director of the MURI, Value-centered information theory for adaptive learning, inference, tracking, and exploitation.
Prof. Hero and Prof. Jeff Fessler wrote a seminal paper in 1996 on prediction algorithms. Those techniques are now part of the standard toolbox for performance benchmarking of prediction algorithms. The approach has been applied to sensor networks, medical image reconstruction, cell phone localization, radio tomography, and Internet traffic measurement.
In related work, Jeff Fessler is using available data to influence his work on medical imaging. Raj Nadakuditi is developing a new theory, called random matrix theory, to improve the quality of information obtained from sensors and sensor networks. Laura Balzano is using signal processing to undercover hidden patterns in “noisy” data.
Jeff Fessler, William L. Root Professor of Engineering, is a world-renowned leader in medical image reconstruction. He has revolutionized the theory and practice of medical imaging with his group’s groundbreaking mathematical models and algorithms that significantly improve both patient safety and image quality. He has produced major improvements in the theory, design and clinical use of scanners in three of the principal clinical scanner modalities: radionuclide imaging (PET/SPECT), magnetic resonance imaging (MRI), and X-ray computer tomograhy (X-ray CT).
Fessler’s research work has been utilized in a major medical scanner called Veo, manufactured by General Electric and introduced at the University of Michigan hospital in 2012. Veo allows CT scans to be performed using a significantly lower dose of radiation than a conventional scan. It is not a new type of machine, but a new way of processing data.
He has collaborated with other U-M scientists on an algorithm for single-photon emission computed tomography that has benefited thousands of cardiac patients. His research has resulted in lower radiation dosages and improved medical diagnoses. His group is currently working to speed up the time it takes to process a low-dose CT scan, in order to make it useful as a screening tool for lung cancer. In addition, Jeff’s group is using data science to achieve ultra-low dose CT image reconstruction.
One unusual aspect of Prof. Fessler’s research is its transparency. He was one of the pioneers in open research, making his data widely available to the public. Other researchers can therefore more easily build on his research, ultimately leading to better health care for all.
Communications and Information Theory
Dave Neuhoff, Joseph E. and Anne P. Rowe Professor of Electrical Engineering, is an internationally recognized expert in information theory and communications. His work in source coding, quantization theory, channel modeling, source-channel coding, Shannon theory, and data synchronization have had a major impact on the field.
Source coding is the process of encoding visual, audio, or other types of information using fewer bits than an un-encoded representation would use. He also specialized in channel coding, which is the process of encoding information so that it can be successfully decoded after passing through a noisy channel. Applications include data compression, quantization, wired and wireless communications, and sensor networks. His work has impacted image and video coding, and codes for audio compression.
In 1989, Prof. Neuhoff spent a sabbatical year in the Signal Processing Research Department at AT&T Bell Labs. His research on facsimile transmission of images led to a number of key contributions in the fields of image compression and halftoning. He is widely recognized as one of the pioneers in the area of model-based halftoning, which has had a major impact on the printing industry and digital photography, especially on halftoning for inkjet printers.
In the early 1990’s, he came up with an important formal proof related to joint source channel coding, which became popular with the advent of cell phones and other wireless communication devices.
Prof. Neuhoff published a study on optimal quantizers for Gaussian sources in the late 1990’s, and his results remain relevant at least a decade later. He was President of the IEEE Information Society and a member of its Board of Governors. Prof. Neuhoff served the department for decades as Associate Chair, with a special focus on graduate education.
More recently, wireless communications has become a primary research focus with the rise of cell phones and other forms of mobile devices. The greatest accomplishment of the project on low-energy electronics design for mobile platforms resulted from the joint effort by Wayne Stark, Stéphane Lafortune, and Demos Teneketzis. They designed a highly efficient wireless system that integrated all of the various layers of the wireless network system. It was the first design of its kind to integrate the design from the physical layer to the transport layer.
Robotics is an interdisciplinary area of investigation that often requires expertise in electrical engineering, computer science, and mechanical engineering. At Michigan, ECE faculty have been involved in robotics from the perspective of Control, specifically dynamical systems and nonlinear control, and more recently, Computer Vision.
Prof. Dan Koditschek led the robotics area during his time here from 1993-2005. He was a collaborator in producing RHex, an autonomous, hexapod robot that was modeled after the motion of insects, in particular, the cockroach. The robot received extensive attention in the media for its ability to navigate uneven terrain at a good speed, and its ability to perform a wide variety of behaviors. It is still being developed at the University of Pennsylvania, where Koditschek was named Department Chair of Electrical and Systems Engineering when he left Michigan. Koditschek was an expert in dynamical systems theory.
This approach to robotics research is being taken up again at Michigan by Shai Revzen, who spent three years at University of Pennsylvania as a postdoctoral researcher before coming to Michigan in 2011. He runs the Biologically Inspired Robotics and Dynamical Systems (BIRDS) lab. Prof. Revzen believes that the next frontier in robotics is to design robots than can adapt to unforeseen situations. With unlimited robotic assistance tailored to a task in the moment, exploration and discovery could be greatly enhanced.
Jessy Grizzle is a worldwide leader in nonlinear control theory and its applications. He turned his attention to the application of control theory to robotics when he visited a bipedal robotics lab in France during a sabbatical in 1998. Grizzle developed algorithms to analytically control how the bipedal robot named RABBIT would walk, departing from the typical trial-and-error approach that characterized robotic walking up to that point. His efforts resulted in landmark research, published in 2002, that resolved a longstanding theoretical issue of how to systematically create and stabilize periodic orbits for a class of underactuated hybrid systems. Researchers around the country have used Grizzle’s theory and applied it to their own robotics work.
His success with RABBIT led to Prof. Grizzle’s first funding specifically applicable to robotics – and the robot known as MABEL. MABEL made the national and international news when she became the fastest bipedal robot with knees in 2011. MABEL is now on display at the Chicago Field Museum, and her successor, MARLO, is learning to walk unassisted by a lateral boon (used to steady RABBIT and MABEL).
The University of Michigan is investing in the future of robotics with a newly-approved $54M robotics center, which promises to consolidate and expand existing robotics research throughout the College of Engineering and beyond. The center will offer state-of-the-art facilities in a 3-story, 100,000 square foot building on North Campus. ECE faculty are excited at the promise the new space offers for increased collaboration and synergy of effort.
Control, Automobiles, and Transportation Systems
While working at Ford, Grizzle was able to precisely regulate the air-fuel ratio in automobile cylinders. This work led to an award-winning paper published in 1992 from the IEEE Vehicular Technology Society, and 15 U.S. Patents on the development and design of environmentally friendly powertrains.
In 2003, Prof. Grizzle received the Control Systems Technology Award for the development of fuel-efficient and environmentally friendly automotive powertrains through innovative application of control theory. And more recently, he designed a power management control strategy for hybrid electric trucks. His design was put up again that of Eaton Corporation in a competition for a new parallel-hybrid-electric delivery truck for Federal Express. Grizzle’s power management design was superior, and enabled Eaton to win the right to provide HEV technology to FedEx.
Kan Chen, internationally recognized expert in automatic control and systems science, joined Michigan in 1970 as the Paul G. Goebel Professor of Advanced Technology; he was named professor of electrical and computer engineering in 1972.
Chen co-directed the Intelligent Vehicle-Highway Systems (IVHS) project, initiated in 1988, and was director of the IVHS Laboratory in the department. IVHS was defined as the integration of information technology with automotive and highway technologies to help relieve traffic congestion, improve safety, and reduce pollution and energy wastes. There was an educational component that consisted of a graduate level research seminar, alternating with a speaker series. After 5 years, the seminar became a regular graduate course, intended to be a cross-departmental series of lectures and discussions. The course was an integral part of the Certificate in Transportation Studies.
The IVHS program ran concurrently with the University of Michigan Transportation Research Institute (UMTRI), established in 1965. UMTRI’s mission is to enhance highway safety. The Director of UMTRI was co-director of the IVHS program, and Chen became affiliated with UMTRI in 1989.
In a 1990 report of the IVHS activities in North America, co-authored with Bernard Galler, Chen stated the four projects in this area established at Michigan were: traffic modeling, human factors, system architecture, and collision prevention. He called this the first, and to date the only, university program in IVHS education.
ECE faculty participating in the program included Stéphane Lafortune, co-PI of the traffic modeling project, and Dr. Marlin Ristenbatt, director of communications projects. Prof. Galler was director of system architecture.
According to Chen, there was a healthy amount of research in this area during the 1960’s and 1970’s, but due to lack of government funding, research in the area of advanced vehicle-highway systems dwindled in the 1980’s. As of 1990, funding was on the upswing – probably a reaction to the huge programs initiated in Europe and Japan in 1988.
In 2013, the Michigan Mobility Transformation Center was established as a partnership with government and industry to dramatically improve the safety, sustainability and accessibility of the ways that people and goods move from place to place in our society. Safety and reduced energy consumption are key goals of the center – which in this age includes connected vehicle systems, driverless vehicles, shared vehicles and advanced propulsion systems. MCity, which opened in 2015, was built as a test environment for automated vehicles. With UMTRI and M-City, Michigan stands poised to produce real breakthroughs in a system that appears poised to make dramatic improvements in traffic safety and automation.
One way that may happen is through research in cyber-physical systems, which is impacting automobile safety features (adaptive cruise control), the safety of busy intersections, and the coordination of complete transportation systems (airlines, automobiles, trains). Cyber-physical systems (CPS) are smart networked systems with embedded sensors, processors and actuators that are designed to sense and interact with the physical world. They support real-time and guaranteed performance in safety-critical applications. ECE faculty working in this area today with a transportation focus include Jessy Grizzle, Stéphane Lafortune, and Necmiye Ozay.
Optics – Legacy of Greatness
Emmett Leith’s breakthrough in practical holography in the 1960’s led to a surge of interest in the field (see the section above on SAR and Holography). By the late 1960’s, Ann Arbor was known as the “holography capital of the world.” In 1961, Michigan achieved another historic milestone in the history of Optics – the birth of nonlinear optics.
Back in 1961, Peter Franken, Alan Hill, Wilbur Peters, and Gabriel Weinreich, physicists working in the Randall Lab on Central Campus, observed for the first time the second harmonic generation in light. This discovery was made possible due to the invention of the laser the previous year. This discovery led to a revolution in optical physics that has opened up the entire electromagnetic spectrum, making possible laser generated radiation from terahertz frequencies to the X-ray regime. Though the milestone was achieved by physicists, it set the stage for engineers to embark on decades of inventions and scientific discoveries of their own over the coming decades.
Applications of nonlinear optics include fiber-optic telecommunications, biological imaging, highly accurate GPS clocks, quantum communication, terahertz radiation (to see safely through clothing, for example), cloaking devices, and even the generation of electricity.
However, research in optics in the department, nonlinear or otherwise, skipped nearly a generation between Leith’s work in SAR and Holography and the mid to late 1980’s.
In fact, when Duncan Steel, Robert J. Hiller Professor, was a student at Michigan in the early to mid 1970’s, he recalled that there was little activity within the department in optics. Wanting to study lasers, he earned a master’s degree in both EE and Nuclear Engineering, because Nuclear was at least doing some work in laser fusion. Prof. Duderstadt was an advisor of his, and was instrumental in bringing Steel back to Michigan in 1985. It’s probably not an overstatement to say he and Chuck Vest were responsible for reinvigorating the entire field of Optics at Michigan by making this a priority area of faculty hiring. Prof. Vest was a professor of Mechanical Engineering who conducted research in holographic measurement early in his career, inspired by Prof. Leith.
Dean Duderstadt described his vision for Michigan becoming a leader in applied optics, as opposed to basic research in optics in the mid 1980’s. He believed that over the next two decades, optics will change from being primarily an area tied to physics to being an engineering discipline. This vision is now a reality at Michigan.
Following are descriptions of some of the key research and technology that has occurred in the area of Optics and Photonics from the mid 1980’s to the present time.
Ultrafast Lasers and an Optics Industry in SE Michigan
A luminary in the world of photonics, Gérard Mourou came to Michigan in 1988, where he founded the NSF Science and Technology Center for Ultrafast Optical Science in 1991. Ultrafast lasers was an area that was ripe for development, as other schools with strong optics programs did not focus in that area.
Mourou had achieved breakthrough research in chirped pulse amplification (CPA) for lasers with a colleague at the University of Rochester in 1985, and was recognized as one of the world’s leaders in the development of ultrafast lasers. CPA enabled a thousand-fold increase in laser peak power and opened the field of relativistic optics, which remains a very active field of physics even today.
Driving the early days of CUOS in the 1990’s was the development of ultrafast titanium-sapphire amplifiers, a new class of ultrafast laser combining high peak power with short pulses. Prof. Ted Norris invented the ultrafast high-repetition-rate Ti:sapphire amplifier in the early 90s, and in 1992, the 250-kHz Ti:sapphire regenerative amplifier. Both lasers can be found in over a thousand laboratories throughout the world in universities, national laboratories, and industry.
Mourou’s next major breakthrough was in femtosecond ophthalmology, or laser surgery. This technology led to the CUOS spinout, Intralase, founded in 1997. With their newly created ultrafast lasers, the company was able to do eye surgery without leaving any tears of the surrounding tissue, enabling blade-free LASIK surgery.
CPA enabled the miniaturization of high power, high intensity lasers, so that a laser fitting on a table-top could achieve peak power of a petawatt (1015 W, or a million billion watts). One such laser, called HERCULES (High-Energy Repetitive CUos LasEr System), was built at CUOS by a team led by research scientist Victor Yanovsky. HERCULES is a table-top size laser that set the world record for high intensity in a laser back in 2003, and has held it ever since. The ultra-fast laser pulse generated by HERCULES is 50 times more powerful than all the world’s power plants combined. HERCULES presents remarkable opportunities for deepening our understanding of fundamental science, as well as for expanding practical applications in materials science, biology, and medicine.
Mourou retired in 2004 with 17 patents to his name to pursue new opportunities in Europe. He was elected to the National Academy of Engineering in 2002 “for the introduction of Chirped Pulse Amplification technique enabling high-intensity lasers.”
While most high-power ultrafast lasers rely on “open-cavity” design, Prof. Almantas Galvanauskas has been defying conventional wisdom by pursuing high-power ultrafast laser pulse generation in optical fibers. After proving the viability of ultra-short-pulse lasers using optical fibers, he received a $7M grant from the Army Research Office through the Joint Technology Office for High Energy Laser development to explore, among other things, high power operation of innovative fibers. He invented a new class of fiber called chirally coupled core (CCC) fiber. The idea was so new that people were skeptical it could work, but it worked on the first attempt. Research is continuing in this area.
In 2010 and in collaboration with Prof. Federico Capasso at Harvard University, Norris made the first ever observation of ultrafast electron transport dynamics and coherent pulse propagation in quantum cascade lasers (QCL’s). This discovery opens up new possibilities for being able to generate short pulses from QCL’s across the infrared region of the spectrum.
Quantum Science and Computing
Quantum computers are the considered the best option for uncrackable encryption codes – increasingly a concern for national security. In 1998, Duncan Steel, Robert J. Hiller Professor, and his group were the first to demonstrate coherent optical control of a single quantum dot. This work led to the idea that quantum dots could be used to build quantum computers. A quantum dot acts like a transistor in a conventional computer.
In 2000, Steel’s group (in collaboration with UC San Diego and the Naval Research Lab) made the first demonstration of optically-induced quantum entanglement in a single quantum dot, and used this to make the first universal quantum gate in a solid-state device.
In 2003, in collaboration with researchers at the Naval Research Lab, Michigan State University and UC-San Diego, Prof. Steel demonstrated the first controlled NOT-gate in a semiconductor, achieved by all optical control in a semiconductor quantum dot without the need for attaching wires. This demonstrated the potential for coherent, optically driven quantum computing in scalable architectures – an advance that generated significant attention in the scientific community.
In 2008, Prof. Steel and the same research group took yet another important step toward practical quantum computing when they became the first to control the inherent duality of a qubit, or quantum bit. “We are the first to show that you can do this to a single electron in a self-assembled quantum dot,” Steel said. “If you’re going to do quantum computing, you have to be able to work with one electron at a time.”
In 2013, Steel and colleagues demonstrated quantum entanglement between an electron spin state and a photon polarization state, both resulting from their association with a quantum dot. By doing so, they were able to prove the phenomenon known as quantum entanglement – something so far-out even Albert Einstein called it “spooky,” and he was the one who proposed its existence. This was a major accomplishment that was mirrored by two unrelated groups working on the same problem. Though the processes used were slightly different, the results were similar and corroborative.
In related work, Prof. Bhattacharya’s group is perfecting a device that can generate the photons needed for quantum computing and quantum information processing. In 2013, Prof. Bhattacharya and his team combined quantum dots, GaN nanowires, and electrical injection to create a device that is capable of producing a single photon at a time, while controlling the polarization of the photon. Both attributes are key to accomplishing certain types of quantum cryptography.
Solving a tunneling physics paradox
In 2006, Prof. Herb Winful resolved a paradox that had puzzled the physics community since 1932. The question was why particles seem to travel faster than the speed of light when passing through a barrier, but not when they travel through empty space. Prof. Winful worked out his theory mathematically, using photonic band gap structures. His result confirmed Einstein’s theory of relativity, and finally explained a seeming paradox about the way particles move through space. Prof. Winful co-organized an event celebrating 50 years since the invention of nonlinear optics at Michigan in 2011.
Fiber Optics and Supercontinuum Lasers – Practically Speaking
Prof. Mohammed Islam developed Raman fiber optic amplifiers, a breakthrough technology for long-haul telecommunications, and introduced it into the marketplace by starting the company Xtera Communications in 1998. The company has been listed on Nasdaq as XCOM since 2015.
In 2004, Prof. Islam founded Omni Sciences, Inc. based on his near-infrared and mid-infrared broadband lasers. He has continued research with the company and in 2010, developed a mid-infrared supercontinuum laser that could blind heat-seeking weapons from a distance of 1.8 miles away. His laser is the first to operate in longer infrared wavelengths that humans can’t see, but can feel as heat.
In 2012, working with the Air Force Research Labs, Prof. Islam developed a supercontinuum laser that can show what objects are made of, potentially helping military aircraft identify hidden dangers such as weapons arsenals far below. Beyond military applications, this device has the potential to improve upon today’s full-body airport screening technologies.
Finally, Prof. Islam has adapted his technology for medical applications. A holy grail for doctors, patients, and engineers alike is to build a device that will allow for non-invasive glucose monitoring. He has come closer to this goal than anyone thus far, and is actively pursuing this line of research.
Electricity from Light
In 2011, Prof. Stephen Rand and his group discovered a dramatic and surprising magnetic effect of light that could lead to solar power without traditional semiconductor-based solar cells. In the process, they overturned a century-old tenet of physics.
Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.
This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation. It was this discovery that led to the establishment of the Center for Dynamic Magneto-Optics (see above).
Michigan has a long-standing reputation for being a world leader in the area of remote sensing that goes back to the 1980’s. It is a reputation built on the work of Prof. Fawwaz Ulaby, considered the Father of microwave remote sensing. When he was hired in 1984, Prof. Ulaby had already directed a nationally recognized program in remote sensing. He continued in the same vein at Michigan when he landed the NASA Center for Space Terahertz Technology in 1988.
That same year, Prof. Ulaby developed the Michigan Microwave Canopy Scattering model (MIMICS). This technique for the remote sensing of biomass (in particular, tree canopies) has been widely used and cited by the research community. Prof. Kamal Sarabandi worked on the project as a graduate student, and wrote his dissertation on electromagnetic scattering from vegetation canopies. His dissertation demonstrated pioneering work in the use of imaging radar systems for monitoring vegetation at the global scale. Many of his algorithms and theoretical models are considered classics and are heavily used by remote sensing practitioners even today.
By the late 1990’s, MIMICS was able to determine with increasing sensitivity biomass above and below ground. It was sent on board the 1994 Space Shuttle, and continues to be the most advanced radar system to ever fly in space.
In 1994, Fawwaz Ulaby, Kamal Sarabandi, and other members of their group were instrumental in the design and calibration of the Shuttle Imaging Radar that flew on NASA’s Shuttle Imaging Radar-C (SIR-C) mission in 1994. This was, and may still be, the most advanced radar system to ever fly in space. It mapped large portions of the Earth’s land surface, and resulted in the launch of later satellite missions by Canada, Japan, and the European Space Agency.
Prof. Sarabandi was later involved in the Shuttle Radar Topography Mission (SRTM), which provided data to generate the first nearly global, high-accuracy topographical map of the Earth. The shuttle was launched aboard the Space Shuttle Endeavor on Feb. 11, 2000. The calibration techniques Sarabandi used to validate the map are now the standard approach used worldwide.
Soil Moisture and Climate
Snow and ice levels have serious ecological consequences. “California is in a drought not because of a lack of precipitation, but because of a lack of snow in the Sierras,” explains Prof. Sarabandi. “The same thing is happening in India. In the Himalayas – if it rains and doesn’t snow, the water just goes away.”
Understanding the phenomena at play in these regions can help to better manage resources. Being able to anticipate a drought, for example, would help mitigate water waste and preserve reservoirs.
As early as the 1970’s, Prof. Tony England was among the scientists who realized that you couldn’t understand global climate and the human effect on climate without considering the atmosphere, the ocean, and the water cycle because they were all interrelated. England saw that hydrologists did not look at the water cycle in a global perspective, and he realized it was because they lacked the tools to do so. England’s team was the first to incorporate microwave brightness to determine levels of moisture in the soil, among other things. He built instruments to calibrate and validate information received from Space not only for Michigan, but other institutions.
In the early 1990’s, Prof. Ulaby wrote a seminal paper about microwave remote sensing of terrestrial snow. He was elected to the National Academy of Engineering in 1995 for contributions to the science and technology of radar remote sensing and its applications, and was awarded the Thomas Edison Medal in 2005.
Prof. Kamal Sarabandi and his team constructed the most powerful radar calibration device in the world to interface with NASA’s newest orbiting satellite, called Soil Moisture Active Passive (SMAP), which launched Jan. 31, 2015. SMAP is a 5-year mission that will measure the amount of water present in the top 2 inches of soil around the entire Earth (excluding the Poles). The data collected by SMAP is expected to improve our ability to forecast the weather, monitor droughts, predict floods, enhance crop productivity, and understand the Earth’s water, energy, and carbon cycles. SMAP is the first satellite ever built to specifically target soil moisture.
Building on the tools and knowledge gained over the past two decades, Prof. Sarabandi will lead an effort to explore the fundamental capabilities of remote sensing through a new grant funded by NASA. The new program aims to create theoretical models for remote sensing of ice and snow. Specifically, the research seeks to develop a better understanding of wave propagation and scattering, and to improve tools for future monitoring. This work could feed into the development of new sensors for a variety of remote sensing applications. Eventually, after enough data is gathered, techniques for reversing these problems as they unfold may be possible.
Radios were among the core early technologies that kept electrical engineers busy in the early decades of the 19th century, and all radios need antennas to convert electric power into radio waves to transmit and receive information. Radio waves are electromagnetic waves, and the antenna couples the electrical connection of transmitters and receivers to the electromagnetic field. The first antenna was built by Heinrich Hertz in 1888, just a year before the first course in electrical engineering was taught at Michigan. Hertz did this reportedly to prove James Maxwell’s theory. With the rise of electronics and computers in the middle of the century, followed by the extreme shrinking of electronics in the late 19th century and wireless applications in the 20th century, this area of research has continued unabated.
Prof. Chen-To Tai was an acknowledged leader in this area. He was elected to the National Academy of Engineering for “For basic contributions to the advancement of electromagnetic theory and its application to antenna design,” in 1987. He also received the IEEE Heinrich Hertz Medal in 1998.
Prof. Tai joined the department in 1964. His accomplishments were summarized by Prof. Senior for the National Academy of Engineering Memorial Tributes: “Professor Tai is recognized throughout the world for his research on antenna theory, electromagnetic theory, and applied mathematics. His extension of Hallén’s pioneering work on antennas to coupled cylindrical antennas established the foundation of multielement array antennas, which are used extensively in a variety of radio systems. His refinement of Schelkunoff’s biconical antenna theory provided a much-needed understanding of how antennas can be designed to operate over a wide band of frequencies.”
A year before he retired in 1986, Prof. Tai was honored by his colleagues and former Ph.D. students in a special session at the 1985 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting.
Terahertz antenna arrays, sources, and circuit components were pioneered in the late 1980’s and throughout the 1990’s within the Center for Space Terahertz Technology.
In 2000, an electromagnetic metamaterial program was established under the direction of Prof. Sarabandi in collaboration with the Materials Science Department under a MURI DARPA program. Metamaterials refer to man-made materials that exhibit properties not observed in nature. Through this five-year program, novel magneto-dielectric, circuit-embedded, electromagnetic band-gap, reactive impedance surfaces and metasurfaces for antenna miniaturization were demonstrated for the first time. This was the first such program dedicated to these particular areas of research.
Unique research in the application of metamaterials to electromagnetic devices is being carried out by Prof. Anthony Grbic, who received a Presidential Early Career Award for Scientists and Engineers (PECASE) in 2009 for his work in this area, three years after joining the department.
Prof. Grbic’s research with Prof. Robert Merlin in the department of Physics in the area of near-field superlenses using near-field plates (NFP) is of great interest to the scientific community. NFP’s hold promise for a number of areas including high resolution probing devices, quasi-optical and optical components, devices for wireless non-radiative power transfer, as well as antennas and nano-antennas.
In other research with Prof. Merlin, Prof. Grbic focused microwaves to specks 20 times smaller than their wavelength and five times smaller than other devices have achieved. This development could allow advances such as laptop computers that recharge without plugging in, higher-resolution microscopes for observing molecules, and CDs that can store vastly more data.
In 2011, Prof. Grbic and Prof. Forrest led the development of a process for mass-producing antennas so small that they approach the fundamental minimum size limit for their bandwidth, or data rate, of operation. This could lead to new generations of wireless consumer electronics and mobile devices that are either smaller or can perform more functions.
Computational Electromagnetics (CEM)
Computational electromagnetics (CEM) involves modeling how the electromagnetic field interacts with physical objects and the environment. It is important to the design and modeling of antenna, radar, satellite and other communication systems, optical, nanophotonic and electronic devices, medical imaging, and other applications and devices. The field has grown in response to the computational power available to engineers for modelling through computer simulation.
Eric Michielssen, Louise Ganiard Johnson Professor of Engineering and Associate Vice President for Advanced Research Computing, is an acknowledged leader in the field. Through his fundamental contributions, researchers have been able to tackle very large and multi-scale computational problems not feasible previously.
In recent work, he applied his techniques to a research project initiated by Prof. Luis Hernandez-Garcia in Biomedical Engineering related to transcranial magnetic stimulation, a brain stimulation technique that is used to treat tough cases of depression. Prof. Grbic contributed to design of the device. The resulting device is expected to open up a lot of opportunities to treat depression and other mental illness, as well as probe the brain.
Prof. Michielssen has been editor-in-chief of the International Journal of Numerical Modelling: Electronic Networks, Devices and Fields since 2010. He co-chaired the Committee on Mathematical Foundations of Uncertainty Quantification, Validation, and Verification that led to, Assessing the Reliability of Complex Models, published by the National Academies Press in 2012. He is currently Director of the Michigan Institute for Computational Discovery and Engineering (MICDE).
Nanotechnology is science, engineering, and technology conducted at the nanoscale, which is about 1 to 100 nanometers. Research in nanotechnology is the key to future transformative advances in electronics, medicine, computing, and energy. A number of faculty in ECE work with nano-sized materials, many of them already discussed with respect to the devices they are building (ie, LEDs, OLEDs, Lasers, Solar Cells, Displays, Lighting, Quantum Computers, Memristors).
Unfortunately, the semiconductor industry is not currently capable of manufacturing many forms of technology based on nano-sized components. Major governmental programs have been initiated to assist in new forms of nanomanufacturing.
Profs. Guo and Zhong, in collaboration with Prof. Steven Yalisove (MSE) and Prof. John Hart (MIT), have their own program in scalable nanomanufacturing. They are using ultrafast femtosecond lasers to build and scale up carbon-based nanostructures, such as carbon nanotubes and graphene.
Prof. Becky Peterson uses solution-based nanomanufacturing techniques to create nanoscale features via ink-jet printing. By selective surface energy patterning, she can scale down the gate length of printed thin film transistors for high-performance, flexible, large-area, and printable electronics.
During the past decade, Prof. Guo and his group have been perfecting a technique for roll-to-roll nanolithography. Nanoimprint lithography enables large area, low cost fabrication of nanoscale structures. In addition, Prof. Guo’s group built a prototype device for high-throughput and high-resolution nanoscale patterning. His method is being used by major companies in Japan and Korea for commercial applications.