Design of circular polarized microstrip aperture coupled patch antenna for 5.8 GHz ISM band

The demand for using wireless communication systems which make mass memory information and high speed contact possible has increased, recently. A built-in microwave antenna is necessary for such systems. This paper presents the design of an aperture coupled modified cross-slot microstrip patch antenna with four new slots generating a circular polarization and using a microstrip substrate produced by plane type printing technology which meets such a demand. The antenna is characterized by small size, light weight, and multifunctional operation. As a result, a return loss of -40 dB at the center frequency 5.84 GHz was obtained by simulation of the ISM band with an operation frequency 5.8 GHz and a return loss of -37 dB at 5.79 GHz by actual measurement, suggesting that the match between the feeding line and radiation patch is better than the existing aperture coupled cross slot microstrip antenna, and the axial ratio is also good