Polarization agile microstrip antenna for wireless communication

A polarization agile single feed square microstrip patch antenna is proposed for wireless communication. The proposed antenna consists of two perpendicular slots placed on the probe fed microstrip patch. Two diodes are incorporated into the slot at appropriate positions. The length of the slots changes according to the `ON´ or `OFF´ states of the diodes and the antenna can radiate right hand circular polarization (RHCP) or left hand circular polarization (LHCP). The proposed antenna shows good impedance bandwidth and axial ratio bandwidth for the polarization states. A prototype of antenna is fabricated on a 40×40mm RT Duroid substrate of dielectric constant ε_r=2.2 and height 3.18mm and the measured results are presented. This antenna would be useful for satellite communication and wireless local area networks (WLAN) application.