Design of a circular polarization array antenna using linear polarization patches

This paper presents a new circularly polarized array antenna using linearly polarized microstrip patches with a gain of 7.47 dBi. The array structure consists of four square patch antennas with feed network. The feed network is designed using microstrip lines on the obverse side of the dielectric substrate and slot line on the reverse side of the substrate. The Teflon glass fiber substrate is used with a permittivity of 2.15. The design frequency of the proposed array antenna is 10 GHz where simulated return loss is less than -45dB. 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. Advanced Design Systems (ADS) by Agilent Technologies is used for the simulation of the proposed array antenna.