5G Multilayer Slot Array Antenna Fed by Integrated Substrate Groove Gap Waveguide for 26 GHz Band

We present a 5G multilayer slot array antenna in the 26 GHz band, fed by an integrated substrate groove gap waveguide (ISGGW). In contrast to previous works, we chose to populate the ISGGW and the intermediate “cavity” layers with a printed “Mushroom” type unit cell in order to appropriately guide the electromagnetic wave. The design allows for a multi-layered architecture, that is supported by the configuration of parallel Artificial Magnetic Conductors (AMC) and Perfect Electric Conductor (PEC) structures at the intermediate, in-contact, surfaces of the layers. The presence of parallel AMC and PEC surfaces avoids any electromagnetic leakage among them, regardless of any air gap existence. Unwanted air gaps between the layers of a multilayer structure can be caused by surface roughness and imperfect flat surface presence. The multiple stacked layers of the proposed structure are robust to such gaps underlining the work's significance. The impedance bandwidth $(\mathrm{S}_{11} < -10\ \text{dB})$ of 7.4% covers the frequency range from 25.13 GHz to 27.05 GHz, the realized gain varies between 8–12 dB, and the efficiency ranges between 50% and 80% over the operating band.