A 3-bit phase shifter with high-power capacity based on composite right/left-handed transmission line

Abstract

A miniaturized 3-bit phase shifter with high power-handling capacity is designed based on the use of a single composite right/left-handed transmission line (CRLH-TL) unit cell. PIN diodes mounted on the fingers of the CRLH-TL unit cell are used as switches to control the phase shift of the input signal. Different phase shifts are achieved by using different states of the switches determined by the 3 controlling bits of the phase shifter. The surface current flowing through each of the switches is only a fraction of the total current through the device, so the power handled by each of the PIN diodes is much smaller than the total power through the device. The phase shifter is designed to provide a phase-shift range from 0° to 157.5° at a step 22.5° and operate in the frequency band from 9 to 10 GHz. Simulation results and measurement results of the prototype agree closely and show that the phase shifter has much higher power-handling capacities than that of the PIN diode and low insertion losses across the operating frequency band. © 2010 Wiley Periodicals.