A Novel Reconfigurable Microstrip Patch Antenna With Polarization Agility in Two Switchable Frequency Bands

A novel reconfigurable microstrip-fed patch antenna with polarization agility in either of two bands is proposed in this communication. Frequency reconfigurability is achieved by connecting an additional small patch to the main patch through a p-i-n diode. Each corner is cutoff from the main patch through a narrow L-shaped cut to get polarization reconfigurability. In addition, the impedance and axial ratio bandwidths are enhanced by using the proximity-coupled feed. Both prototypes are designed, fabricated, and tested. The measured results agree well with the simulated results in all cases. Also, the proposed microstrip-fed antenna is tested at high RF input power. The proposed structures are simple, low profile, low cost, and have simple bias circuitry. The proposed antennas are capable of operating in three polarization states, i.e., left-hand circular polarization, linear polarization, and right-hand circular polarization in two frequency bands. The proposed structures are best suited for modern advanced wireless communication systems such as LTE and 5G.