Phase shifters for dielectric waveguides

The use of dielectric waveguides for high microwave frequencies in place of metallic rectangular waveguides has been suggested for many years. Besides the problems of manufacturing very small metallic rectangular waveguides for use above 90 GHz and the increasing attenuation due to the skin effect and surface roughness there is also the problem of attenuation and repeatability in the connectors. This latter problem is particularly acute when measurements are made using standard impedances. Following the successful six-port reflectometer made in dielectric guide the next project at Kent involves a multistate reflectometer in dielectric guide. A multistate reflectometer has the advantage over a six-port reflectometer in that it requires two less power meters. In order to achieve this, the device also needs a means of changing phase. This present paper describes a novel broadband phase shifter which has been designed for use in multistate reflectometer. The whole device will then enable the user to make very accurate measurements of phase and amplitude in the range 70-140 GHz for not very much more than the cost of a swept source