An Analog X-Band Phase Shifter

A hybrid-coupled phase shifter has been fabricated monolithically using reverse-biased Schottky varactor diodes to continuously vary phase with an analog control voltage. A phase shift of 105° is obtained at X-Band, and wtth design improvements a phase shift of 180° over the full 8-12.4 GHz is expected. Phase shift variation with power level is reduced by using back-to-back varactors on the direct and coupled ports of the coupler. A six-to-one reduction in size compared to a four-bit switched-line phase shifter (also at X-Band) results from this approach.