Design of a Frequency and Polarization Reconfigurable Patch Antenna With a Stable Gain

This paper presents a frequency and polarization reconfigurable patch antenna with a small gain variation. Eight discrete operating frequency bands can be achieved by properly switching shorting pins, and three polarization states, i.e., left-hand circularly polarization, right-hand circularly polarization, and linearly polarization, can be realized simultaneously by adjusting perturbation segments. A stable gain performance is obtained within a wide reconfigurable frequency range, as well as all the reconfigurable polarization states, by utilizing the loss-character of p-i-n diodes when shorting pins are properly switched ON/OFF for different states. A prototype is designed, fabricated, and measured. The simulated and measured results agree as well. The experimental results show that the proposed antenna exhibits a simple reconfigurable network, a wide switching frequency range, a good element gain, and a small gain variation less than 1.8 dB across all the operating states.