A 19 GHz Vector-Sum Phase Shifter Using Active Current-Mode Coupler and Bi-phase Modulator for Satellite Communication

In this paper, we present a vector-sum phase shifter for satellite communication at 19 GHz. The ±I/±Q signals for phase synthesis by vector adder are generated by an active current-mode 90° coupler and two reflection-type bi-phase modulators. In order to save area, we use the single-ended two branches quadrature structure to replace the Gilbert-cell type vector-sum phase shifter. In addition, we use the tail current source to fix the total current for vector adder. The measured average peak gain is -1.2 dB at 19 GHz. The measured average IP
_1db
is better than -17 dBm. The 3-dB bandwidth is from 18.1 to 19.9 GHz. Total de power consumption is only 10 mW for 1.8 V supplied voltage. To our best knowledge, this phase shifter has good gain and low RMS amplitude and phase error among active phase shifter.