Dissertation Defense

Towards Ubiquitous Wireless Power Delivery using Code Division Multiple Access

Akshay Sarin

(passcode: 807801)

The availability of energy is one of the major hindrances to unlocking the massive potential of electronic devices. Powering a highly connected network of devices requires multiple access and a wireless power transfer (WPT) solution that is scalable and capable of maintaining a constant power flow regardless of configuration and changes in the electromagnetic environment. In this work, we present a framework for code division multiple access (CDMA) for enabling simultaneous WPT to possible thousands of devices.

With multiple devices sharing the same electromagnetic space, cross-couplings among multiple devices are unavoidable. This cross-coupling can lead to a multitude of problems including overheating of devices, variations in power transfer, and deterioration of the system efficiency. The existing methods suffer from increasing hardware complexity, computational complexity, and decreasing power transfer rates with an increasing number of devices that limit the scalability and reconfigurability of these techniques.

CDMA-WPT decouples power transfer among multiple devices operating within the same magnetic space with the same hardware by using different digital codes. Thus, CDMA can help expand WPT to possibly thousands of devices. The hardware implementation of CDMA-WPT requires transceivers that can efficiently realize ternary codes. We present an extended current-mode class-D (X-CMCD) for hardware implementation of CDMA-WPT. A design process for practical co-design of high-performance hardware and obtaining a code set for developing a WPT network is also presented.

Chair:  Professor Al-Thaddeus Avestruz