A batteryless payment device is disclosed. According to certain embodiments, the batteryless payment device may include a first communication system and a second communication system, the second communication system being a near-field-communication (NFC) system. The batteryless payment device may also include a power receiver coupled to the first communication system and configured to wirelessly receive power from an external device for powering the first communication system. The batteryless payment device may further include a controller configured to: when the first communication system is powered, establish, via the first communication system, a first wireless connection with a user device; receive, through the first wireless communication, a token from the user device; establish, via the second communication system, a second wireless connection with a payment terminal; and transmit, through the second wireless connection, the token to the payment terminal.

An absorbent article has one or more fluid filter layers to inhibit electrode traces from being exposed to low volumes of fluid to reduce the number of false positives that are indicated by an RFID tag of the incontinence detection pad. An antenna inlay has a sacrificial trace portion to permit testing for proper operation of an RFID chip electrically coupled to the antenna inlay. After testing, the sacrificial trace portion is severed. A fluid barrier layer blocks fluid from reaching portions of electrode traces that are located on a backsheet outside a periphery of an absorbent core of an incontinence detection pad. The power at which an antenna transmits to wirelessly energize a passive RFID tag of an incontinence detection pad is controlled to reduce the number of false positives indicated by the RFID tag.

A method begins by a radio frequency identification (RFID) reader transmitting a first and second radio frequency (RF) signal of a plurality of RF signals, which each include a unique carrier frequency and an instruction to an RFID tag to respond with a received power level indication. The method continues by the RFID reader receiving, in response to the first and second signals sent at a first and second carrier frequency, a first and second response from the RFID tag that includes a first and second received power level indication. The method continues by the RFID reader determining an estimated resonant frequency of the RFID tag based on the first and second received power level indications and the first and second carrier frequencies.

RFID readers may be configured to supply power to tags during frequency hops. When a reader is supplying power to a passive RFID tag via a first RF waveform having a first radio frequency and determines that it is to frequency-hop, the reader may determine whether the tag requires power during the hop. If so, the reader begins (or continues) to synthesize a second RF waveform with a second radio frequency while also synthesizing the first RF waveform, and frequency-hops by transitioning from transmitting the first RF waveform to transmitting the second RF waveform such that the power transmitted during the transition is sufficient for the tag to operate.

A wearable device includes a radio-frequency identification (RFID) tag having a memory that stores identification information. The wearable device also has a power harvesting circuit configured to harness power from electromagnetic radiation. Further, the wearable device has a sensor coupled to the power harvesting circuit and configured to utilize the power to monitor a condition of the wearable device. Even further, the wearable device has a microcontroller coupled to the sensor and configured to write data indicative of the condition to the memory of the RFID tag, wherein the RFID tag is configured to transmit the identification information and the data in response to receipt of the electromagnetic radiation from an RFID reader.

A wireless identification tag for embedding into an electrically conductive surface of a rotatable work tool, the tag comprising at least a first and a second inductive planar loop having corresponding first and second terminals, wherein the first inductive planar loop and the second inductive planar loop are arranged in relation to a common plane and wherein the first inductive planar loop and the second inductive planar loop are arranged to cover separate areas of the common plane, where each area on the common plane is associated with a respective polarity of the magnetic flux normal to said plane.

An absorbent article has one or more fluid filter layers to inhibit electrode traces from being exposed to low volumes of fluid to reduce the number of false positives that are indicated by an RFID tag of the incontinence detection pad. An antenna inlay has a sacrificial trace portion to permit testing for proper operation of an RFID chip electrically coupled to the antenna inlay. After testing, the sacrificial trace portion is severed. A fluid barrier layer blocks fluid from reaching portions of electrode traces that are located on a backsheet outside a periphery of an absorbent core of an incontinence detection pad. The power at which an antenna transmits to wirelessly energize a passive RFID tag of an incontinence detection pad is controlled to reduce the number of false positives indicated by the RFID tag.

An RFID device is provided for communicating with at least one RFID transponder that has a transmitter, a receiver, a transmission antenna and a reception antenna for emitting and receiving RFID signals and has a control and evaluation unit that is configured to transmit and receive an RFID signal in a respective one of a plurality of frequency channels, in particular to encode RFID information into the RFID signal and/or to read information from the RFID signal in accordance with an RFID protocol and to carry out an intensity adaptation of the RFID channel in dependence on the frequency channel used for the transmission and reception.

Various switchable devices including inductive antennas are disclosed. These switchable devices may include one or more RFID tags and one or more switches. Some of these one or more switches are optionally wireless and/or manual. In various embodiments, the switchable devices include are included within cellular phones, security devices, identity devices, financial devices, remote controls, and the like. The switchable devices are optionally configured to perform financial transactions.

A wireless electromagnetic coupler arrangement for reactive near field coupling comprising a sequential array of coupling elements which are geometrically arranged one-or two-dimensionally. By means of feeding an unmodulated wave of electromagnetic energy to each of the coupling elements and a respective associated harvester element, in an initial sensing state, an automatic selection of a single coupling element or plural coupling elements which establish a particularly strong and efficient interaction with an inlay is performed. By means of a respective feedback loop, a switchable array of resistances is used to activate the selected coupling element(s) for coupling of information to/from the loop and to de-activate the remaining coupling elements.