Wideband and High-Gain Corporate-Fed Gap Waveguide Slot Array Antenna With ETSI Class II Radiation Pattern in V -Band

We present a V-band multilayer corporate-fed slot array antenna with wide impedance bandwidth and high efficiency. The proposed antenna consists of three unconnected metal layers based on the recently introduced gap waveguide technology. A 2 × 2 cavity-backed slot subarray acts as the unit cell of the array. The top metal layer contains the radiating slots, the intermediate layer contains the cavities, formed by pins, and the third layer is the ridge gap waveguide corporate-feed network. The latter is realized by a texture of pins and guiding ridges to uniformly excite the cavities with the same amplitude and phase. The proposed antenna fulfills the radiation pattern requirement of the ETSI 320 standard. A prototype consisting of 16 × 16 slots was manufactured by a fast modern planar 3-D machining method, i.e., die-sink electric discharge machining. The fabricated prototype has a relative impedance bandwidth of 17.6% with input reflection coefficient better than -10 dB. The Eand H-planes radiation patterns satisfy the ETSI class II copolar sidelobe envelope, and the measured cross-polar level is more than -30 dB below the copolar level over the 56-75 GHz frequency band. The measured antenna efficiency is better than 60% over the same band.