Wideband circularly polarized antenna array using sequential phase feed structure and U‐shaped radiating patch elements for S‐band applications

Abstract

AbstractIn this article, a 2 × 2 circular polarized (CP) antenna array, which is using sequential rotation (SR) technique in feeding network, has been introduced. The feeding network uses two 90° arcs and several rectangular lines with the same width. The length of these elements is multiple of λg/4 to produce 90° phase difference in 4 outputs of feeding network. By connecting the patch elements to the feeding network, which have been surrounded with radiating patch elements, design of 2 × 2 patch array has been completed. This array antenna with an incomplete ground which helps to have a better impedance matching, has been caused to reach a wider axial ratio (AR) and impedance bandwidth. The prototype of the proposed antenna array is built to validate the antenna performance. By using these techniques, a common bandwidth of 1.15 GHz has been achieved for impedance bandwidth (S11 < 10 dB) and AR bandwidth (AR < 3 dB) and 7.5 dBi maximum gain. In addition, the gain is more than 4 dBi in desired frequency range. According to the frequency range of 2.8‐3.95 GHz, the proposed antenna is suitable for S‐band applications.