Nov 9 (Mon): "High-efficiency mm-wave Power Amplifiers and Packaging Design," Ahmed Ahmed, ECE PhD Defense

https://ucsb.zoom.us/j/88063314183?pwd=ZDVBTk9vYitmOHpQRmUxWG9walFzdz09

ABSTRACT

There is an increasing demand for high data-rate communications. In this research, we consider the next-generation systems (100-340GHz), as millimeter frequencies permit a much larger spectrum, and shorter wavelengths provide massive MIMO array and high image resolution. This thesis focuses on building the hardware and necessary components for such systems. It is very challenging to produce decent efficiency and power at mm-wave frequencies as the gain drops significantly and the loss increases. Additionally, mm-wave packaging requires advanced assembly techniques. Here, we introduce a network theory to analyze the amplifier’s degrees of freedom and achieve the maximum PAE. The proposed theory considers the stacking and parallel power approaches using two-port techniques. This theory establishes a design framework for designing high-efficiency power amplifiers. We also demonstrate record efficiency mm-wave power amplifiers (140, 210, and 300GHz) with moderate output power. The 140G Hz amplifiers produce measured output power (20.5-23dBm) with a record efficiency of 17.8-20.8% PAE. We also present 17.7-18.5dBm output power over the 190-210GHz frequency range with high efficiency of 6.9-8.5% PAE. Finally, a massive MIMO demonstration and mm-wave packaging are presented. We started with on-waver CMOS transmitters and receivers, then moved to a single packaged CMOS channel transmitter with eight-element series fed patch antenna, which has an EIRP of 13dBm at 135 GHz. Finally, we built a tile holding eight elements transmitter or receiver, which is currently in fabrication. The thesis covered the design and implementation of high-efficient packaged transmitters that prove the feasibility of the mm-wave communication system.

BIO

Ahmed Ahmed received his B.S. and M.S. degrees in Electrical Engineering from Cairo University, Cairo, Egypt, in 2012, and 2015 respectively. He is currently pursuing the Ph.D. degree in Electrical and Computer Engineering at the University of California, Santa Barbara, CA, USA. His main research interests include RF and millimeter-wave integrated circuits in silicon and III–V technologies for wireless communications, mm-wave packaging design and phased-array systems.

Hosted by: Professor Mark Rodwell

Submitted by: Ahmed Ahmed <a_s_ahmed@ucsb.edu>