TE-mode radiation from a flanged parallel-plate waveguide with dielectric plug shaped like a wedge

Flanged waveguides are used in phased arrays and flush-mounted antennas as an efficient means for the radiation of microwave energy. Dielectric plugs, pushed into the radiating ends, are often applied for protection of the above structures from the environment and for impedance matching. In the past, the related radiation problems have been investigated in the case of inserts possessing a rectangular outline. In the present paper we study the radiating structure with a plug shaped like a wedge from the waveguide end. The method of analysis is domain product technique. Two distinctive cases, concerned with the absence or existence of the higher order mode propagating inside the dielectric, are examined. In the latter case, as it is demonstrated with the aid of a computational experiment, modifying the profile of the insert affects the radiation pattern considerably. In particular, a suitable choice of the shape of the plug can provide, along with reduction of the reflected wave amplitude, the narrowing of the beamwidth as well.