Gap-Waveguide Cavity Slot Array Based on Two Metal Layers at 120 GHz

A novel gap-waveguide cavity slot array is proposed at 120 GHz. To reduce the conductor loss, the cavity based radiator with virtual electric walls are introduced instead of traditional waveguide slot array. The cavity is first designed at TE880 mode where 8×8 slots are supported for radiation. Then a center-fed E-plane waveguide is employed to feed the cavity. Two rows of in-line longitudinal slots are etched on the double broadsides of E-plane feeding waveguide which provides alternative excitations for the desired operating mode. By inserting the feeding waveguide into the cavity, the array antenna can be fabricated in two metal layers with a simple stack assembly. The simulated impedance bandwidth is 13.3% with a peak gain of 25 dBi at 120 GHz.