Archimedean spiral antenna based on metamaterial structure with wideband circular polarization

A small aperture spiral antenna with circular polarization based on metamaterials is presented. The proposed antenna is composed of an Archimedean spiral, split ring resonator (SRR) and a microstrip exponentially tapered balun for antenna feeding. The SRR is composed of three split rings, which has negative permeability characteristics. By adding SRR to the periphery of the Archimedean spiral, the antenna axial ratio (AR) performance in low frequency is enhanced, and the antenna electrical length is extended, which achieves antenna miniaturization. The proposed antenna has -10 dB impedance bandwidth and 3 dB AR bandwidth from 1.7 GHz to 7.5 GHz. In the operation band, the peak gain is always greater than 2 dBi. Furthermore, the measured antenna efficiency is always more than 60% in the whole operation bandwidth. The volume of the proposed antenna is 65 x 65 x 50 mm3. The experimental results corroborate the computational results, indicating that the designed antenna can be widely used in broadband circular polarization systems, such as mobile communication, radar detection and other fields.

Automated summary

This paper presents a small aperture spiral antenna with circular polarization based on metamaterials. By adding split ring resonators, the antenna's performance at low frequencies is enhanced, and antenna miniaturization is achieved. The antenna has wide impedance and axial ratio bandwidths, making it suitable for applications in mobile communication, radar detection, and other fields.