A high yield ultra small passive vector modulator based phase shifter for smart antenna combining at C-band

Abstract

A passive, vector modulator based phase shifter MMIC is presented, using a commercial 0.6 /spl mu/m GaAs MESFET process. A continuously adjustable 360/spl deg/ phase control is achieved by combining and weighting two out of three vectors with phase offsets of 120/spl deg/. The amplitude of the vectors are controlled by cold FETs. The phase offsets of 120/spl deg/ are generated by LC low/highpass filters. A loss of 9 dB and a -1 dB input compression point of 16.5 dBm were measured. The circuit requires an effective chip size of only 0.5 mm/sup 2/, which to our knowledge is the smallest continuously adjustable 360/spl deg/ phase shifter, reported to date.