Design of Wideband Slot Array Antenna by Groove Gap Waveguide in Millimeter Waves
Paper in proceedings, 2018
The newly introduced gap waveguide technology offers non-contact waveguide configurations so that the good electrical contact between different metallic layers can be avoided. Thereby, the gap waveguide structures are relatively simple to manufacture, especially at millimeter and sub-millimeter wave frequencies. This work systematically presents a high-efficiency corporate-fed slot array antenna based on groove gap waveguide in the millimeter waves. A cavity-backed slot sub-array is firstly designed in a groove gap waveguide cavity. The cavity is fed through a coupling hole from groove gap waveguide distribution network at the bottom layer. The sub-array is numerically optimized in an infinite array environment. Low side lobes are obtained in the both E- and H-planes by diagonal placement of the radiation slot rotating by 45 degrees. Furthermore, the radiation narrow slot pair is adopted so that the good cross polarization is achieved. The fabricated antenna depicts more than 25% bandwidth with input reflection coefficient better than -8 dB and the aperture efficiency higher than 60% with around 25 dBi realized gain between 70 and 90 GHz. The measured cross polarization level is below -27 dB, which satisfies the ETSI standard.