A 6-bit Active Phase Shifter with Quadrature Outputs

A quadrature phase shifter with balanced QAF loading and improved accuracy in 28 nm CMOS technology is designed for a DC or low-IF receiver with double quadrature down-conversion. Quadrature all pass filter (QAF) with LC resonance at outputs achieves high quadrature accuracy over the whole phase shift range and a wide bandwidth. The designed digital-to-analog convertor (DAC) controls the amplitude of I/Q path and generates a phase shift angle covering 360°. The phase shifter operates in 24-30 GHz range. The phase shifter shows simulated rms phase error of < 2° and rms gain error of <0.2 dB at 24-30GHz, consuming 11.6mW.