A Non-Contacting Waveguide Backshort for Submillimeter Wave Applications

A novel design for non-contacting waveguide backshorts, suitable for applications into the Thz frequency range, is described in this paper. The new approach, which has been developed by the Jet Propulsion Laboratory (JPL), circumvents severe machining and mechanical strength difficulties related to the miniaturization of standard microwave backshort designs. The new design consists of a metal bar with rectangular or circular holes cut into it, which is covered with a dielectric (mylar) layer to form a snug fit with the broadwalls of a waveguide. A method of numerical analysis called the mode-matching/space domain integral equation (MMSDIE) technique is described herein, followed by a discussion of measured and theoretical results.