A Compact Axial-Mode Helical Antenna Based on Spoof Surface Plasmon Polaritons

Abstract

A compact axial-mode helical antenna (AMHA) is presented based on spoof surface plasmon polaritons (SSPPs). The proposed antenna consists of an SSPP waveguide, a matching metal strip, and a reflective metal ground. To achieve miniaturization and good circular polarization (CP) performance, an SSPP waveguide formed by a periodically slotted metal strip wound around a uniform foam cylinder surface is designed as the radiation part of AMHA. Compared with the traditional AMHA using metallic strip line, the SSPP AMHA can reduce the length of metal strip by 20%, while the physical aperture, height, and volume are reduced by 36%, 20%, and 49%, respectively. Experimental results demonstrate that the antenna has good radiation performance in the operation frequency from 3.3 to 4.7 GHz with a gain of 9.6 dBic at the central frequency. In addition, the size of the proposed SSPP AMHA can be further significant reduced if the foam rod in the center of helix is replaced by a high-permittivity dielectric rod. The proposed SSPP AMHA has the advantages of compact size and good CP radiation performance, which may find potential applications in radar and wireless communication systems.