A Millimeter-Wave Spoof Surface Plasmon Polaritons-Fed Microstrip Patch Antenna Array

A novel spoof surface plasmon polaritons (SSPPs)-fed microstrip patch antenna with a simple low-profile geometry is proposed. The method of inserting an open-ended planar single-conductor SSPPs section into the supporting substrate under the rectangular patch is investigated originally to excite the required TM10 mode and to achieve the promising impedance matching simultaneously. An impedance bandwidth of 8.2%, stable linearly polarized unidirectional radiation, and a gain of around 6 dBi are confirmed by a fabricated prototype. A planar single-conductor parallel feed network consisting of the SSPPs power dividers is then analyzed, which has a simulated insertion loss of around 8 dB. By combining the feed network with the patch elements, a 1 x 4 SSPPs-fed microstrip patch antenna array is designed in the Ka-band. The measurement verifies the stable radiation with an enhanced gain of about 12 dBi across the operating band. Due to the planar configurations with low cost and promising performance, the presented SSPPs-fed patch antenna and array may find potential applications in future millimeter-wave wireless systems.