A Low Sidelobe Double-Layer Corporate-Feed Array Antenna by Inverted Microstrip Gap Waveguide at 28 GHz

In this work, a novel low sidelobe array antenna is designed at 28 GHz. The proposed array antenna is fed by classic full-corporate double-layer distribution networks based on newly introduced inverted microstrip gap waveguide. In order to achieve low sidelobe property, a classic Taylor synthesis method is adopted in this work. In the distribution network, a couple of unequal power dividers with identical output phases are applied for the low sibelobe in this work. The fundamental radiator is 2×2 slot sub-array, and the entire array antenna is constructed by 8×8 of such kind sub-arrays. The simulated radiation patterns show that the first sidelobe levels, front-back ratio of both E-plane and H-plane from 26.5 GHz to 29.5 GHz are very well improved compared with traditional ones with the equal amplitude and phase distribution networks. The input impedance bandwidth is about 12% with the reflection coefficient below -10 dB, and the gain is more than 29 dBi from 26.5 GHz to 29.5 GHz.