Abstract: A method for operating a microradio is provided. The method includes storing first parasitic energy received during a first charging cycle, powering a receiver with the stored first parasitic energy during a listening period, receiving a wireless control signal during the listening period, storing second parasitic energy received during a second charging cycle, selectively powering a transmitter with the stored second parasitic energy, and transmitting a signal responsive to the received wireless control signal.

Abstract: A microradio is provided with a hysteretic switch to permit an optimum range increasing charging cycle, with the charging cycle being long relative to the transmit cycle. Secondly, an ensemble of microradios permits an n2 power enhancement to increase range with coherent operation. Various multi-frequency techniques are used both for parasitic powering and to isolate powering and transmit cycles. Applications for microradios and specifically for ensembles of microradios include authentication, tracking, fluid flow sensing, identification, terrain surveillance including crop health sensing and detection of improvised explosive devices, biohazard and containment breach detection, and biomedical applications including the use of microradios attached to molecular tags to destroy tagged cells when the microradios are activated. Microradio deployment includes the use of paints or other coatings containing microradios, greases and aerosols.

Abstract: A Radio Frequency Identification (RFID) device antenna has a feed region of interdigitated fingers. The interdigitated fingers have parallel centerlines and are spaced one from another. A chip having opposing ends overlays opposing interdigitated fingers. A coupling is established between the chip and the antenna at the interdigitated fingers.

Abstract: A Radio Frequency Identification (RFID) device antenna has a feed region of interdigitated fingers. The interdigitated fingers have parallel centerlines and are spaced one from another. A chip having opposing ends overlays opposing interdigitated fingers. A coupling is established between the chip and the antenna at the interdigitated fingers.