An X-band 22.5°/45° digital phase shifter based on switched filter networks

Abstract

The design approach and performance of a 22.5°/45° digital phase shifter based on a switched filter network for X-band phased arrays are described. Both the MMIC phase shifters are fabricated employing a 0.25 μm gate GaAs pHEMT process and share in the same chip size of 0.82 × 1.06 mm2. The measurement results of the proposed phase shifters over the whole operating frequency range show that the phase shift error is less than 22.5°± 2.5°, 45°± 3.5°, which shows an excellent agreement with the simulated performance, the insertion loss is within the range of 0.9–1.2 dB for the 22.5° phase shifter and 0.9–1.4 dB for the 45° phase shifter, and the input/output return loss is better than –12.5 and –11 dB respectively. They also achieve the similar continuous wave power handing capability of 24.8 dBm at 10 GHz. The phase shifters show a good phase shift error, insertion loss and return loss in the X-band (40%), which can be employed into the wide bandwidth multi-bit digital phase shifter.