Design of a compact ultra wideband quadrature digital MMIC phase shifter

A compact 4~16 GHz ultra-wideband reflection-type quadrature phase shifter is designed for wideband phased array radar systems and electronic beam steering application. The proposed phase shifter operates in 4~16 GHz band. It is composed of a lumped 3-dB coupler using inductive coupling and a pair of reflective terminating circuits of serial-parallel LC structure. This lumped topology reduces chip area and associated die cost. The completed MMIC phase shifter is 0.6mm × 1.70mm (1.02mm²) using a 0.15μm GaAs pHEMT technology. The layout simulation results exhibit a typical insertion loss of 4.6dB ± 1.2dB, a return loss better than 14dB and a phase difference of 90°±6° over 4~16 GHz.