Design and Fabrication of the Wideband Circular-Polarization Antenna with Reconfigurable Capability for Communication Links in L and S Bands

In this paper, broadband antennas with reconfigurable capability in circular polarization are presented for use in communication links. To achieve the impedance bandwidth and its relatively good circular motion, a German has been proposed that has a falcate patch and two L-shaped probes for feed lines. The proposed antennas can create a left-hand or right-hand circular polarization using an RF switch located in the feeding network. The two structures are analyzed and simulated. The first structure, which is a single antenna and a sample of which was made, has a measured impedance bandwidth 62% (S11 <-10dB) and 3dB axial ratio 49% (AR <3dB). The second structure is an array antenna 1*2 with two falcate patches, four L-shaped probes, and two Wilkinson power dividers. In this array, sequential rotation feeding networks used for enhancement axial ratio bandwidth. According to the simulated results, the impedance bandwidth and AR of the array antenna are 67% (1.31-2.62GHz) and 60% (1.3-2.4GHz), respectively, which is wider than the single antenna. The maximum gain of the array antenna is 10dB in effective bandwidth. These antennas can be used in communication links, electronic support measurement, jamming systems in L and S bands.