A noncontact communication medium includes a power generator that has a coil and generates power with application of an external magnetic field from an outside to the coil, a clock signal generator that generates a clock signal using the power, and a processor that operates using the power and executes processing on a command included in the external magnetic field. In a case where a processing result signal indicating a processing result obtained with the execution of the processing is transmitted to the outside through the external magnetic field by the coil, the processor changes a signal level of the processing result signal according to intensity of the external magnetic field.

Systems and methods are described for low power radio devices. A first radio-based computing devices emits wireless power signals which are received by a plurality of second radio-based devices. A sensor controller of the one or more second radio-based devices determines if an interrupt signal is to be transmitted to an associated at rest microcontroller, to cause the microcontroller to prepare to receive or emit a radio information signal.

A wearable payment device, such as a finger ring worn by a user, communicates payment data to a payment reader that uses the payment data in order to request a payment transaction. Such wearable payment device may be conveniently carried by and accessible to the user such that utilization of the payment device for the payment transaction is less burdensome for the user, thereby encouraging use of the payment device for payments. Indeed, in some cases, such as when the payment device is implemented as a finger ring or other type of jewelry, the user may be encouraged to carry the payment device in an exposed manner such that it is readily available for the payment transaction without the user having to search in a wallet, pocket, or purse.

A Radio Frequency Identification (RFID) tag is disclosed. The RFID tag includes an antenna port to receive an input AC signal and a self-tuning circuit coupled with the antenna port to optimize signal strength of the input AC signal during a self-tuning phase. The RFID tag further includes an AC limiter configured to limit the voltage of the input AC signal to a preconfigured limit and a limiter controller configured to disable the AC limiter during the self-tuning phase and re-enable the AC limiter after the self-tuning phase. The self-tuning phase occurs prior to the data communication period in which the data stored in the RFID tag is transmitted back to a reader.

A voltage limiter incorporated in a radio frequency identification (RFID) integrated circuit (IC) for a RFID tag is disclosed. The RFID IC includes a radio frequency (RF) rectifier and a clock generator. The RF rectifier is configured to convert an AC signal received from an antenna incorporated in the RFID tag to a DC signal. The voltage limiter includes a current sink device coupled between output of the RF rectifier and ground and a charge pump to control conduction of current through the current sink device to limit output voltage of the RF rectifier to a predefined voltage level.

A wearable payment device, such as a finger ring worn by a user, communicates payment data via an antenna to a payment reader that uses the payment data in order to request a payment transaction. The wearable payment device can tune the antenna to enhance performance of the antenna. The wearable payment device can measure a characteristic of the antenna and perform an assessment of the performance of the antenna based on the measured characteristic. The antenna can be tuned, such as by changing the impedance of the antenna, based on the assessed performance of the antenna.

A wearable payment device, such as a finger ring worn by a user, communicates payment data to a payment reader that uses the payment data in order to request a payment transaction. Such wearable payment device may be conveniently carried by and accessible to the user such that utilization of the payment device for the payment transaction is less burdensome for the user, thereby encouraging use of the payment device for payments. Indeed, in some cases, such as when the payment device is implemented as a finger ring or other type of jewelry, the user may be encouraged to carry the payment device in an exposed manner such that it is readily available for the payment transaction without the user having to search in a wallet, pocket, or purse.

A circuit for an NFC chip is described herein. According to one exemplary configuration, the circuit comprises an antenna for near field communication, an antenna resonant circuit which has an adjustable resonant frequency, a temperature sensor and a controller circuit coupled to the temperature sensor. The controller circuit is designed to change the resonant frequency of the antenna resonant circuit according to a temperature sensor signal provided by the temperature sensor.

Embodiments of the present disclosure generally relate to a wireless identification tag for association with a product to enable product self-identification and system and methods for use thereof. In one implementation, the tag may include at least one antenna tuned to receive energy transmitted at one or more frequencies within certain frequency bands. The tag may also include at least one transmitter that may be configured to send at least one identification signal. The tag may also include at least one circuit. The at least one circuit may be configured to detect whether energy is received in a certain frequency band, and to cause the at least one transmitter to operate in a mode corresponding to the certain frequency band.

Embodiments of the present disclosure generally relate to an appliance for holding electronically tagged products and for recording an association between the tagged products and the appliance, and system and methods for use thereof. In one implementation, the appliance may include a housing defining a cavity for retaining the electronically tagged products. The appliance may also include an exciter integrated with the housing and configured to trigger tags of the products to cause the tag of each product to transmit a unique tag ID. The appliance may also include a receiver for receiving transmission of each unique tag ID. The appliance may also include a communicator for outputting indications of identities of electronically tagged products retained in the cavity.