Antenna systems that utilize polarization diversity are gaining popularity due to the development of wireless communication in recent years. The antenna systems have been used in many areas such as wireless local area networks (WLAN) and microwave tagging systems. They are also utilized to realize frequency reuse for doubling the system capability in satellite communication systems.
In this paper, it is presented a novel antenna for polarization diversity. The proposed antenna is aperture coupled circularly polarized patch antenna with switching elements. The antenna is designed and simulated at 2 GHz by using Ensemble software. The square patch in proposed antenna has a pair of truncated corners and the microstrip feed line has schottky diodes as switching element. A patch antenna with four schotttky diodes can achieve right hand circular polarization (RHCP) and left hand circular polarization (LHCP) depend on switching states.
Each of two schottky diodes were placed at /4 from branch-off point of power divider and these diodes are shorted at high level voltage.
Simulation results of proposed antenna show 7.5 % 10 dB impedance bandwidth and 1.2 % axial ratio. The return loss of the antenna is mesured and agree well with simulation results.