A 2-10 GHz Digital CMOS Phase Shifter for Ultra-Wideband Phased Array System

This paper describes a digital true time-delay phase shifter implemented in 0.18-μm CMOS process for ultra-wideband phased array application. The phase shifter exhibits linear phase change versus frequency, digital control, low insertion loss, and reduced circuit size. Shunt-series peaked load increases the bandwidth of the phase shifter, yielding a flat gain response over a wide bandwidth. The fabricated circuit demonstrates a measured 157.5° phase tuning range in steps of 22.5°at 10 GHz.