Shared-Aperture Antennas Based on Even- and Odd-Mode Spoof Surface Plasmon Polaritons

In this communication, we propose a method of designing shared-aperture antennas based on excitations of both even- and odd-mode spoof surface plasmon polaritons (SSPPs). The antenna consists of a feeding monopole and a tapered SSPPs structure, both of which are placed vertically on a metallic ground. Due to tilted electric vectors of the monopole in near fields, both even- and odd-mode SSPPs can be excited. Standing waves of even-mode SSPPs on the SSPPs structure will enable broadside or tilted radiation, while traveling waves of odd-mode SSPPs on the tapered end will enable endfire radiation. Therefore, such an antenna configuration can achieve broadside, tilted, and endfire radiations. As an example, a shared-aperture antenna operating in C/X/Ku-bands was designed, fabricated, and measured. Both the simulated and measured results verify that the antenna can achieve broadside radiation in 4.68-4.83 GHz, tilted radiation in 8.51-8.82 GHz, and endfire radiation in 11.00-17.38 GHz, with peak gains about 2.7, 3.5, and 6.8 dB, respectively. The antenna itself can work in multiple bands with customized radiation patterns, without using several antenna radiators and complex feeding network. This communication provides an effective method of designing shared-aperture antennas in future lightweight and multifunctional wireless communication systems.