Design of a Circular Polarization Array Antenna with Dual-Orthogonal Feed Circuit

In this paper, the design of a circularly polarized array antenna at 10 GHz frequency is presented. The proposed antenna consists of a 1x2 array antenna with feed circuit. To realize circular polarization, dual-orthogonal feed circuit is used that excites two orthogonal modes with equal amplitude but quadrature in phase. Feed circuit is designed using microstrip lines and slot lines where microstrip lines are placed on the top surface of the substrate and slot lines on the reverse side of the substrate. The feed point is chosen in such a way that it provides the each patch element two RF signals with 90 degrees phase difference. Therefore, the circular polarization is realized by employing microstrip-slot feed circuit. "Both-Sided MIC Technology" is used to design the proposed array antenna as it gives flexibility in the design process. The simulated return loss of the proposed array antenna is less than -45 dB at the design frequency. The 3 dB axial ratio bandwidth of 0.8% is obtained. The structure and the basic behavior along with the simulation results of the proposed circularly polarized array antenna are demonstrated in this paper.