A novel C-band CMOS phase shifter for communication systems

This paper deals with the design methodology and characterization of a novel integrated differential phase shifter suitable for RF communication systems. The differential phase shifter is realized using a cascade of /sub 0//4 varactor tuned LC ladder networks connected between driving amplifiers and is designed in a conventional 0.18 /spl mu/m CMOS operating out of a 1 V supply. The circuit provides up to /spl pi//3 (rad) maximum phase shift for every segment of the LC ladder network (twice as reported in previous work). The implemented differential phase shifters; provide up to 2/spl pi/ (rad) absolute phase shift and /spl pi/ (rad) relative phase shift with sine phase transfer functions for 8 GHz RF signals. Each differential phase shifter occupies an area of 400 570 /spl mu/m/sup 2/ and dissipates 170 mW.