Switched transmission-line type Q-band 4-bit MMIC phase shifter using InGaAs pin diodes

Abstract

A fully integrated Q-band 4-bit MMIC phase shifter with InGaAs pin diodes has been designed and fabricated. To achieve low insertion loss and good phase shifting characteristics at Q-band frequencies, topology based on a switched transmission line is employed using a thin-film microstrip line structure implemented in the MMIC fabrication process. The fabricated phase shifter has demonstrated good performance such as an insertion loss of less than 6.1 dB in the frequency range 46-49 GHz with a small intrinsic chip size of 2.48 x 0.87 mm. The results show the best insertion loss characteristic among the switched transmission-line type phase shifters reported at Ka- and Q-band frequencies.