Comparison of Feeding Network Topologies in Air Waveguide Slot Array Antennas for Automotive Radar Applications at 79 GHz

In this study, three different feed networks for air waveguide slot array antenna structures are introduced: side-fed, middle series feeding networks, and semi middle series feed networks. Middle series networks provide precise control over phase and amplitude due to their central placement of the feeding network. Conversely, side-fed configurations may have limited control over mutual coupling and phase alignment among array elements but offer spatial efficiency compared to middle fed setups. In the third design, a synthesis of both structures’ advantages is achieved: the middle fed structure enables amplitude and phase adjustments for each slot, while the side fed design minimizes spatial occupation compared to the middle fed series feed network.