Broadband and tunable RF phase shifter

Abstract

This thesis explores the design, simulation, and analysis of broadband and tunable RF phase shifters for next-generation wireless and radar systems. As demands for wideband, reconfigurable, and compact RF components grow in 5G/6G networks, phased-array antennas, and radar systems, phase shifters have emerged as critical elements enabling beam steering and signal control. This work investigates various phase shifter architectures and presents two primary design approaches: a broadband phase shifter utilizing weakly coupled microstrip lines, and another employing multimode resonators with λ/4 stubs to achieve 90° phase shifts over a wide frequency range. Both designs were implemented on single-layer substrates to ensure low cost, minimal insertion loss, and planar integration. Additionally, the thesis proposes compact filtering phase shifters capable of simultaneously achieving phase control and frequency selectivity. Two such designs—a 45° and a 90° phase shifter—are developed using stepped impedance lines and open-circuited stubs, demonstrating high return loss, low insertion loss, and stable phase performance over wideband ranges. Simulation results validate the proposed designs, highlighting their feasibility for integration in advanced RF systems requiring precise phase shifts with compact, efficient layouts. This work contributes to the development of passive, low-loss, and frequency-agile phase shifters suitable for scalable RF front-ends and modern communication infrastructures.