A novel wide-band tunable RF phase shifter using a variable opticaldirectional coupler

We present a novel RF phase-shifter design with a usable bandwidth of 80:1. The design is verified through demonstration of a proof of concept device, consisting of a readily available voltage variable optical coupler fabricated from LiNbO3, combined with an fiber-optic delay line. The design is analyzed theoretically and measurement of the device confirms the predicted range of operation. Methods of extension of this range of operation are discussed