A Compact and Reconfigurable Circularly Polarized Complementary Antenna

A circular-polarization-reconfigurable complementary antenna with compact size is presented. The proposed antenna has a low-profile planar structure that exhibits an omnidirectional circularly polarized (CP) radiation pattern achieved by combining a printed electric dipole and a quarter-wave shorted microstrip patch. By manipulating the dc biasing voltages, the operation of the antenna can be switched between left-hand circular polarization and right-hand circular polarization. Moreover, by using the meandering line methodology, the lateral dimension of the printed electric dipole is reduced by 25% compared to the conventional design. A prototype of the proposed structure is designed and fabricated for potential use in multifunction application. Measured results are in good agreement with simulation. The CP radiation feature and polarization reconfigurability are also sustained by measurement.