A compact wideband circularly polarized fractal slot antenna with rectangular island for X-band satellite applications

Abstract

AbstractThis paper introduces a compact, circularly polarized spidron-fractal slot antenna with a rectangular island. The reflection-coefficient |S11| of the proposed antenna covers the band from 7 GHz to 10 GHz. The proposed antenna is circularly polarized with an axial-ratio (AR) bandwidth that extends from 7 GHz to 10 GHz. It offers simultaneous dual circular polarization (RHCP and LHCP). The gain of the proposed antenna varies between 4 dBi and 6.9 dBi. The simulated efficiency reaches 97%. The overall dimensions of the antenna are 19.7 x 23 x 0.508 mm3 (0.55λ0 x 0.65λ0 x 0.014λ0), making it suitable for CubeSats with limited surface area. The proposed antenna can be employed for both the X-band satellite downlink (from 7.25 GHz to 7.75 GHz) and uplink (from 7.9 GHz to 8.4 GHz) frequency bands. Additionally, the antenna can be utilized in small satellite Synthetic-Aperture-Radar (SAR) systems operating from 9 GHz to 10 GHz, military applications, and RFID tag tracking-equipment. A prototype of the proposed antenna has been fabricated and then measured using Vector-Network-Analyzer (VNA) and inside an Anechoic chamber. The measurement results of the proposed antenna are in excellent match with the simulated results.