Study on DNA-like SSPPs Structure and Its Application on Circularly Polarized Antenna

In this paper, a novel DNA-like all-metal structure, which can realize quasi-omnidirectional radiation with circular polarization (CP) in even mode and endfire directional radiation with CP in odd mode is proposed. The dispersion characteristics of the SSPPs structure in odd mode and even mode are thoroughly investigated. The proposed structure consists of two main components: the double helix arms and strips. The radiation fields of the helix arms and strips under the current distribution of the odd mode and even mode are independently analyzed to understand their contributions to the overall field. To excite the odd mode, a circular monopole is employed, while even mode is excited using a microstrip line. Experimental results demonstrate that the odd mode exhibits an impedance bandwidth of 39.9% and an axial ratio (AR) bandwidth of 33.7%, while the even mode achieves an impedance bandwidth of 22.2%, along with quasiomnidirectional CP radiation with AR bandwidth of 1.03%.