Thickness effects in slots located in various positions in rectangular waveguide

Theoretical expressions for the equivalent circuit parameters of slots of finite wall thickness are obtained in terms of the parameters of aero-thickness slots of identical cross-section dimensions. The thick slots are treated as composite structures consisting of appropriate junctions and lengths of connecting waveguide, and the parameters of the junctions are determined from those of corresponding zero-thickness slots. The latter parameters have been developed in previous work by our group. The thick slots considered include transverse slots coupling identical guides, transverse slots radiating from the end of the guide, slot-coupled E-plane Tees, and slots radiating from the broad face of the guide. Precision measurements have been taken at a wavelength of 3.2 cm as a function of nail thickness, and excellent agreement is obtained with the theoretical predictions.