Circular polarized microstrip patch array antenna for wireless LAN applications

Circular polarization plays a vital role in the wireless communication systems due to their flexibility in orientation at transmission and reception of signals. For proper reception of signal, the antenna performance has to be improved with high main beam gain and increased directivity. The gain and directivity of circularly polarized single patch antenna is increased by array antenna. The patch antenna produces circular polarization with dual and orthogonal feed lines and the same is achieved with a single diagonal feed to the patch. This work attempts to build a 2.4 GHz circular polarized four element broad side array antenna with diagonally fed patch antennas without polarizer. The designed structure is simulated to study the performance with various orientations of the patches for the diagonally fed array. The array is combined with matched strip lines and an impedance transformer at the output to obtain a return loss of 17 dB, gain of 8 dB and directivity of 10 dB at 2.4 GHz.