Design of circular polarized microstrip aperture coupled patch antenna for 5.8GHz 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 the systems. This paper designed aperture coupled modified cross-slot microstrip patch antenna with four new slots generating a circular polarization, using a microstrip substrate produced by plane type printing technology which meets such demand and is characterized by small size, light weight, and multifunction, and interpreted its characteristics. As a result, a return loss of -40[dB] in the center frequency 5.84[GHz] was obtained by simulation of ISM band with operation frequency 5.8[GHz] and a return loss of 37[dB] in the 5.79GHz by actual measurement, suggesting that the match between feeding line and radiation patch is better than existing aperture coupled cross slot microstrip antenna, and the axial ratio is also good.