A Gap Waveguide-Based D-Band Slot Array Antenna With Interdigital Feed Network

This work presents a high-gain D-band slot array antenna with a corporate-fed distribution network designed by the gap waveguide. The gap waveguide technology is employed for overcoming the challenge of appropriate electrical contact related to the mechanical assemblage of the antenna feed network and the radiation layer. The antenna includes
$24\times16$
slots and the basis of the antenna interdigital feeding network includes the ridge and groove gap waveguides. A standard WR-6 waveguide flange at the bottom is used to excite the presented antenna. To understand the fabrication challenges and tolerance issues at around 140 GHz, an antenna prototype was made by standard computer numerical control (CNC) milling techniques. The results show that an impedance bandwidth of 5.5% (141.8–149.8 GHz), efficiency higher than 78%, and a peak gain of 33.8 dBi are achieved for the proposed
$24\times16$
-element array antenna. According to the results, the presented planar array is a good option for D-band applications and can be used as the building block to develop high efficiency and high gain upper mm-wave antennas.