The bias control circuitry 1212 may be configured to perform one or more function analogous to those of bias control circuitry 1008 described with reference to FIG. 10. For example, the bias control circuitry 1212 may be configured to reverse bias the frequency mixer 1208 to turn the target device 1200 off (e.g., so that the target device 1200 stops transmitting RF signals in response to receiving RF signals). In some embodiments, bias control circuitry 1212 may be configured to apply a forward bias to frequency mixer 1208 to increase the gain of the dual band antenna 1206 so as to increase the amplitude of the RF signals transmitted by the dual band antenna 1206. For example, in some embodiments, the bias control circuitry 1212 may be configured to apply a forward bias to the frequency mixer 1208 so as to optimize the impedance match between the dual band antenna 1206 and the frequency mixer 1208.
FIG. 12B is a diagram of a side view of a target device 1200 in an embodiments, where the oscillator 1204 is realized as a cavity resonator 1207, dual band antenna 1206 is a MEMS antenna, and frequency mixer 1208 is realized as a P or N doped square 1214 disposed on the MEMS antenna 1206. Cavity resonator 1207 is configured to generate RF signals and transmit them to dual band antenna 1206 through air gap. In this configuration, the dual band antenna 1206 may be efficient
