Spatially-Discrete Traveling-Wave Modulated Electromagnetic Structures

Passcode: RadLab

Over the past two decades, metamaterials and metasurfaces have been widely used to provide engineers with material properties that go beyond those found in nature. Metamaterials are engineered structures that can be described by equivalent electromagnetic parameters (like permittivity and permeability).  With recent developments in the fabrication of nonlinear materials and devices, metamaterials with space-time modulated electromagnetic properties are being explored.  These structures can support nonreciprocal (one-way) propagation, frequency-conversion, and amplification.  Traveling-wave modulation is of particular interest due to its simplicity, and is often realized by applying staggered time-modulation signals to a discrete array of unit cells. This modulation is referred to as spatially discrete, traveling-wave modulation (SDTWM).

Analyzing SDTWM structures is challenging due to their complex space-time dependence. The presented research reduces the complexity of analyzing SDTWM structures by leveraging their inherent space-time periodicity. Central to this achievement is an electromagnetic boundary condition that is fundamental to the behavior of SDTWM structures. Based on the derived boundary condition, novel techniques for analyzing SDTWM metasurfaces, antennas, and guided wave structures are examined. Simulation and measurement results will be shown for representative modulated structures whose capabilities transcend those of linear, time-invariant systems; leading to new opportunities in full-duplex communication, reconfigurable electromagnetic devices, and low-noise amplification.

Chair: Professor Anthony Grbic