Compact short circuit for slotted waveguide array BFNs

The design of slotted waveguide arrays with enhanced bandwidth performance always requires the sub-sectioning of radiating and feeding waveguides. Interleaved or in-line configurations are possible for the feeding waveguide sections placing. In the latter case waveguide overlap is typically avoided by employing either a 90°-bent or a 180°-folded short circuit, so locally increasing the antenna thickness. In this work a novel compact short circuit is presented, obtained by means of capacitive irises which allow a 50% size reduction of the short circuit, so that the feeding section can fit in the in-line configuration without overlaps. The effectiveness of the proposed solution is shown through a comparison with the standard approach.