Monolithic Integrated Reconfigurable RF-MEMS Phase Shifters

Abstract

Micro-electro-mechanical systems (MEMS) actuators are a key technology that have been utilized in many real-world applications. This thesis investigates the application of MEMS technology in the design of RF components and reconfigurable phase shifters for use at fifth generation (5G) cellular network mid-band frequencies. The key benefits that MEMS technology offers are very attractive for use in RF applications. RF-MEMS switches provide the advantage of low loss, low power consumption, and high isolation, with the disadvantage of having slow switching speeds, reliability concerns of physical moving structures, and difficult fabrication. This thesis presents the design, simulation, microfabrication, and testing of RF-MEMS devices for use in the 5G mid-band spectrum. This includes monolithic integrated single and multiport RF-MEMS switches, which go on to serve as the foundational components for further complicated RF devices. These switches are implemented to design switched-capacitor banks using metal-insulator-metal (MIM) capacitors and capacitors realized using co-planar waveguide (CPW) stubs. The aforementioned components are then incorporated into a 40° reconfigurable digital RF phase shifter design over the frequency range of 3.4 to 3.8 GHz, and feature enough bits and states to achieve near analog phase shift resolution. A switched-line RF phase shifter is designed using multiport RF-MEMS switches, capable of a true-time-delay (TTD) phase shift of 0° to 320°, in increments of 40°. These two phase shifters are then combined to design a monolithic integrated full range 360° reconfigurable RF-MEMS phase shifter.