Abstract: A method for communicating with a plurality of radio frequency (RF) devices includes transmitting a first signal at a first power level, interrogating RF devices responding to the first signal, instructing the responding RF devices to change state, and transmitting a second signal at a second power level higher than the first power level. The RF devices responding to the first signal do not respond to the second signal upon changing state.

Abstract: A radio frequency (RF) system having omnidirectional functionality, such that the antenna is functional in a generally isotropic manner. The system in one embodiment includes a supporting substrate, a circuit coupled to the substrate, and an antenna coupled to the circuit, the antenna having multiple lobes, wherein responses from the lobes are demodulated and combined at baseband. The circuit can be positioned over a physical area of a portion of the antenna, the antenna acting as a virtual ground plane for the circuit.