Design of n-bit phase shifters with high power-handling capability inspired by composite right/left-handed transmission line unit cells

Abstract

This study presents a design of n-bit phase shifters inspired by the composite right/left-handed transmission line (CRLH TL) unit cells. The phase shifters designed have the advantages of small size, high power-handling capability, low insertion loss, arbitrary phase-shift range and arbitrary step size. PIN diodes mounted on the fingers of the CRLH TL unit cell are used as switches to control the phase incursion of the input signal. Different phase shifts are achieved by using different switch states determined by the controlling bits. As an illustration, three n-bit phase shifters of lengths 2-bit, 3-bit and 6-bit are designed to operate in the frequency band of 9-10 GHz and have the phase-shift ranges from 0° to 67.5° at a step of 22.5°, from 0° to 157.5° at a step of 22.5° and from 0° to 360° at a step 5.625°, respectively. Power-handling capability is analysed using the surface-current density on the CRLH TL cells. Simulation and measurement results agree closely with each other and show that the phase shifters have much higher power-handling capabilities than that of the PIN diodes used and low insertion losses across the operating frequency band. © 2010 The Institution of Engineering and Technology.