A multi-layer gap waveguide array antenna suitable for manufactured by die-sink EDM

In this paper, a multilayer wideband slot array antenna is presented for high gain applications at V-band. The proposed antenna consists of three unconnected metal layers based on the recently introduced gap waveguide technology. A 2×2 cavity-backed slot subarray is fed by a ridge gap waveguide corporate distribution network. The subarray is optimized to have wide bandwidth and low grating lobes in an infinite array environment. A simple slot-tilting method is used to fulfill the radiation pattern requirement of the ETSI 302 standard for fixed radio links. A prototype consisting of 16×16 slots is manufactured by die-sink Electric Discharge Machining (EDM), a fast modern planar-3D spark machining method. The measured antenna has a relative bandwidth of 18% with input reflection coefficient better than -10 dB, and the radiation patterns satisfy the ETSI 302 standard co-polar sidelobe envelope over 56-67 GHz frequency band. The measured total aperture efficiency is over most of the frequency band better than 80%