Millimeter-Wave Filtering Metasurface Antenna Array With Printed RGW Technology

A millimeter-wave printed ridge gap waveguide fed filtering metasurface antenna (MSA) array is presented for 5G applications. The MSA element consists of a parasitic loop and a stacked patch. The elaborately designed parasitic loop around MSA not only provides satisfactory lower stopband performance but also brings an in-band resonance. Meanwhile, another upper edge radiation null is generated by introducing two square-ring slots on the MSA, improving the suppression level. Therefore, with no extra filtering circuits, desirable filtering characteristics are achieved. A 1 x 4 filtering MSA array is fabricated and tested to demonstrate the concept. Based on measurement results, the array prototype exhibits an overall bandwidth of 27.2% within |S-11| < -10 dB. Besides, the average tested gain of about 11.1 dBi is realized, and the gain suppression outside the passband exceeds 27 dB on both sides.