A Magneto-Electric Dipole Antenna With Switchable Circular Polarization

A polarization reconfigurable magneto-electric (ME) dipole antenna with broad bandwidth is proposed and investigated. Two crossed dipoles through a 90° phase delay line, constituting a sequentially rotated configuration, is used to feed the ME dipole. By manipulating the states of four p-i-n diodes which are inserted in the crossed dipoles, the antenna is able to switch the polarization between two orthogonal circularly polarized states. To verify the performance, the proposed antenna is designed, constructed, and tested. Measurements reveal the design obtains an effective bandwidth of 33.3% and a gain of approximately 8.2 dBic for both polarization states. Besides, stable unidirectional radiation patterns with front-to-back ratios higher than 25 dB are also achieved.