Design of a Metasurface Antenna With Pattern Diversity

A dual-port metasurface (MS) antenna for pattern-diversity applications is proposed. The planar MS, consisting of 4 x 4 square patches, is excited by a driven patch. A pair of differential probe feed is used to drive the patch with broadside mode, while a stepped probe feed is employed in the center of the patch to generate conical mode. The capacitive-loaded stepped probe of the center feed is able to adjust the operating frequency of the conical mode and provide the two different modes with a wide overlapped frequency range. A prototype of the antenna was fabricated and measured for demonstration. The measured overlapped bandwidth (|S-11| < -10 dB) is 11.2% ranging from 5.11 to 5.72 GHz. Within the band, the measured peak gain is 11.5 dBi for the broadside mode and 6.8 dBi for the conical mode. High isolation of greater than 32 dB between the two ports is achieved over the band. Benefiting from the gain and bandwidth improvement brought by the MS, the proposed pattern diversity antenna is attractive for many wireless communication systems.