Reconfigurable circularly polarized antenna with frequency agility

Abstract

AbstractA design for reconfigurable circularly polarized (CP) microstrip antennas with frequency agility is described. The main radiating element of the antenna is a suspended patch, and it is connected with two vertical feed probes. When one feed probe is used as a signal input port, the other probe can serve as a perturbation element of the microstrip antenna resonant at the fundamental mode, and consequently a CP radiation is generated. Because the dual probes are arranged in an orthogonal fashion, the antenna can be operated in right‐handed and left‐handed circular polarization modes. To vary the CP operation frequency, four varactors are mounted on the ring slot embedded on the radiating patch. Simulated results indicate that the CP frequency can be continuously tuned from 1.2 to 1.9 GHz with decreasing the capacitance of the varactors. A prototype is also fabricated, and only one DC bias is required to realize the reconfigurable antenna. The design concept of the proposed antenna is shown, and CP performances at different frequencies are also presented.