Design of an x-band microstrip array antenna for circular polarization

In this paper, the design of a circularly polarized array antenna with 9.56 dBi of gain at 10 GHz frequency is presented. The proposed antenna consists of a 2×2 array antenna with feed network where all microstrip patches are linearly polarized. “Both-Sided MIC Technology” is used to design the proposed array antenna. The simulated return loss of the proposed array antenna is less than -35dB. The 3 dB axial ratio bandwidth of 2.21% is obtained. The unequal feed line is used in order to realize 90° phase difference between the linearly polarized patches. Therefore, the circular polarization is realized by the combination of linearly polarized patches and unequal feed line. The structure and the basic behavior along with the simulation results of the proposed linearly polarized array antenna are demonstrated in this paper.