A Metasurface-Based Broadband Circularly Polarized Microstrip Antenna at X-Band

A metasurface-based broadband circularly polarized microstrip antenna is proposed in this paper. The antenna consists of two layers of radiation structure, the upper layer is a circular patch with a rectangular gap, and a coaxial line is used to feed the upper patch, while the lower layer is metasurface, which is composed of 4 by 4 square patches to generate additional resonance. After simulation optimization, the final optimized working frequency band is 8.6-11.S8GHz (the bandwidth is 29.8
^%
). In this frequency band, S11 < −10 dB, AR < 3 dB, and the maximum gain is 7.7dBi with the gain fluctuation less than 2dB. The proposed antenna mainly radiates the right-handed circular polarization wave. In addition, the antenna does not need complicated feeding structure such as a hybrid, and has the advantages of simple structure, small volume, light weight, low cost, convenient processing and easy integration.