Abstract: A radio frequency identification (RFID) tag and reader system including an array of circular resonators with interdigitated capacitor fingers wherein the fingers of each pair are radially aligned and bars disposed between the resonators to reduce coupling between adjacent resonators, wherein subsets of the resonators resonate at respective different resonant frequencies, and the resonators of each of the subsets have the same resonant frequency; and the radio frequency response produced by the tag at a resonant frequency varies depending on the activation of resonators of the subset corresponding to the resonant frequency.

Abstract: A radio frequency identification (RFID) tag and reader system including an array of circular resonators with interdigitated capacitor fingers wherein the fingers of each pair are radially aligned and bars disposed between the resonators to reduce coupling between adjacent resonators, wherein subsets of the resonators resonate at respective different resonant frequencies, and the resonators of each of the subsets have the same resonant frequency; and the radio frequency response produced by the tag at a resonant frequency varies depending on the activation of resonators of the subset corresponding to the resonant frequency.

Abstract: A mm-wave RFID tag interrogation apparatus includes multiple transmitting antennas, and multiple receiving antennas. The transmitting and receiving antennas are spatially distributed and oriented in orthogonal polarization states. A transmitter is coupled to the transmitting antennas, and transmits a corresponding multiple number of separable mm-wave signals. A receiver coupled to the receiving antennas is configured to extract separable components of received mm-wave signals. A processing unit processes the extracted signal components using a synthetic aperture algorithm. An RFID tag, readable by the interrogation apparatus, includes meander-line conductive elements arranged to encode information spatially on a substrate.

Abstract: A mm-wave RFID tag interrogation apparatus includes multiple transmitting antennas, and multiple receiving antennas. The transmitting and receiving antennas are spatially distributed and oriented in orthogonal polarisation states. A transmitter is coupled to the transmitting antennas, and transmits a corresponding multiple number of separable mm-wave signals. A receiver coupled to the receiving antennas is configured to extract separable components of received mm-wave signals. A processing unit processes the extracted signal components using a synthetic aperture algorithm. An RFID tag, readable by the interrogation apparatus, includes meander-line conductive elements arranged to encode information spatially on a substrate.

Abstract: Various embodiments relate to a radio frequency transponder. In one embodiment, the transponder includes: a substrate and at least one planar antenna on the substrate, the antenna having a shape determining a corresponding resonant frequency of the antenna, wherein the antenna is configured to cause a phase difference between backscattered signals generated in response to excitation of the antenna by orthogonally polarized interrogation signals at the resonant frequency, and the phase difference represents a code of the antenna.

Abstract: A radio frequency transponder is disclosed. In one embodiment, the transponder includes: a substrate and at least one planar antenna on the substrate, the antenna having a shape determining a corresponding resonant frequency of the antenna, wherein the antenna is configured to cause a phase difference between backscattered signals generated in response to excitation of the antenna by orthogonally polarized interrogation signals at the resonant frequency, and the phase difference represents a code of the antenna.