Next-Generation Amplifiers for Beyond-5G Applications

Abstract

This thesis focuses on developing indium-phosphide heterojunction-bipolar-transistor-based amplifiers for applications in the RF spectrum above 5G frequencies. Advanced modifications of the Darlington configuration have produced high-gain, high-bandwidth, and low-power amplifiers with DC-200 GHz operating frequencies. Models were developed to improve the ability to predict measurement results, allowing the designs to be fine-tuned for optimal performance. An original figure of merit was designed to compare the prospective performance of the amplifiers with various state-of-the-art publications. The amplifiers produced have higher figures of merit than all state-of-the-art amplifiers examined. Additionally, the use of resettable fuses for high-frequency circuit protection was discussed. These fuses were characterized by their power levels, input return loss, and response time. A set of specifications were developed as the minimum criteria for a fuse to protect a microwave circuit. Fuses of ceramic, polymeric, and electronic types were characterized and compared against the minimum criteria to show that the maturity of the technology is inadequate. This thesis concludes with suggestions for future research.