C-band 6-bit phase shifter for a phase array antenna

A C-band 6-bit digital phase shifter is presented. The phase shifter is based on the synthetic design of a high-pass/low-pass network and the all-pass network. The series scatter restrain method is also discussed. The phase shifter is fabricated in 0.25 mu m GaAs PHEMT technology and developed for C-band phased arrays, and the relative phase shift varies from 0 to 360 in step of 5.625 degrees. The phase shifter, with a chip size of 4 x 1.95 mm(2), has achieved an insertion loss better than 6.4 dB, RMS phase error of less than 1.73 degrees, and an input and output VSWR less than 1.6 at all conditions.