An Investigation of a Variable Waveguide Coupler with 360 Degrees of Phase Control

摘要

A waveguide hybrid coupler was investigated that provides variable control over the phase and amplitude of a signal radiated from a waveguide slot. The control technique was studied theoretically and empirically in two devices, a mechanical unit that incorporated four micrometer-driven probes and an electronic unit that utilized four varactor diodes around the slot. Coupling levels up to -12.3 db were obtained over a 360-degree range of phase control with the mechanical unit and up to -23.0 db over a similar range with the electronic unit. It was found that simple driving functions on the control elements provided theoretically predictable slot phase control, but that coupling variations increased at the higher coupling levels. (Author)