A Wideband True Time Delay in GaAs pHMET MMIC

Abstract

A controllable wideband true time delay based on 0.25 µm GaAs pHMET technology is proposed. The circuit adopts the modified trombone topology to reduce the variation of the insertion loss. Fourth-order and second-order all-pass networks (APN) are applied to the gate and drain respectively to form the step of 12ps delay. The 3-bit control voltage achieves the maximum delay range of 83ps, with the variation of insertion loss less than ±0.8dB. The operation frequency bandwidth is 8-18GHz, and the die area is 1.08mm2 with 110mW consumption.