RF- and DC- line share ring frequency controllable antenna

An RF- and DC-line share ring frequency controllable (shriquen) antenna is proposed, where an anti-series-connected variable-capacitance (varactor) diode pair is loaded in a conductor ring. Reactance diversity is achieved by exchanging DC-bias voltage from positive to negative, or negative to positive. Because the ring serves as a DC voltage feeding line and not only as an RF radiating antenna, neither additional devices for DC of the circuit nor a cable for the DC supply are needed. It is shown that the shriquen antenna can achieve both input impedance matching and diversity effects over the UHF band.