Decade bandwidth 4 bits MMIC phase shifter for T/R modules

This paper presents the design approach and test results of a full passive, decade bandwidth GaAs MMIC, composed by a phase shifter (PS) with a cascaded absorptive SPDT switch, suitable for T/R modules in Active Electronically Scanned Array (AESA). The proposed PS — fabricated using a GaAs 0.25 PHEMT process — combines all-pass filters (APF) with high-pass filters (HPF), in order to provide less than 13dB insertion loss, less than ±20° phase error and less than ±2.5 dB amplitude error in the 0.8–8GHz bandwidth.