A wireless sensor circuit and sensor tag in which the output is directly converted to a frequency response. The sensor circuit includes a buffer transistor having gate, source and drain terminals configured as a source-follower, a gate resistor connected to the gate terminal of the buffer transistor, a supply voltage connected to the drain terminal of the buffer transistor, and an active load element and a capacitive load element connected to the source terminal of the buffer transistor. An input signal having an input frequency is applied to the buffer transistor via the gate resistor and an output signal is generated at the source terminal of the buffer transistor. The output frequency represents a response of the sensor circuit.

One example is directed to a reader device having a first resonance circuit and being configured to interrogate one or more other remotely-located resonance circuits, each associated with a second resonance circuit which may be part of a passive sensor circuit. The first resonance circuit is operated to cause the inductively-coupled oscillating signal to be swept over a range of frequencies and therein cause a jump or sudden transition in a frequency of the oscillating signal while the first and second resonance circuits are in sufficient proximity for inductively-coupling via an oscillating signal via their respective resonance circuits. Sensing circuitry may be used to detect the jump or sudden transition in the frequency of the oscillating signal and, by way of or in response to an indication of timing and/or a set of inductively-related parameters, data is conveyed from the sensor to the reader device via the inductively-coupled oscillating signal.

This tag reader can be applied to a chipless RFID tag having a plurality of resonance frequencies that are associated with identification information. The tag reader is provided with: a radiation unit that radiates electromagnetic waves within a predetermined millimeter wave or microwave frequency band so as to cause sweeping of the radiation frequency; and a detection unit that detects the plurality of resonance frequencies of a chipless RFID tag on the basis of the reflection characteristics of waves reflected from the chipless RFID tag when the electromagnetic waves are radiated.

An IC tag is provided that can adjust the resonant frequency to be within a predetermined range, according to the permittivity of an object to which the IC tag is to be attached, without changing the design of an antenna. The IC tag includes: an IC tag main body having an IC chip and an antenna electrically connected to the IC chip; and at least one resonant frequency adjuster that is stacked as a layer on the IC tag main body and adjusts the resonant frequency of the antenna to be within a predetermined range.

A method includes transmitting, by a radiofrequency identification (RFID) reader device, a first electromagnetic radiation at a first polarization to a scan area and second electromagnetic radiation at a second polarization to the scan area. Re-radiated first electromagnetic radiation is received from an RFID tag located in the scan area at the first polarization. Re-radiated second electromagnetic radiation is received from the RFID tag at the second polarization. A radar image is generated based on the first and second re-radiated electromagnetic radiation. One or more items of information encoded in one or more microstructure elements located on the RFID tag are decoded based on the generated radar image. An RFID reader device and an RFID system are also disclosed.

A system is provided for wirelessly locating objects. The system has a transceiver unit with an antenna array of two partially overlapping coils, which is used in combination with a passive electromagnetic reflector to track or locate the objects. The system is tuned to reflect and receive higher order harmonics of a transmitted signal frequency. The system is reliable in a highly reflective environment with no placement error detection due to reflections. A relatively large distance can be bridged with a minimum power and a small sensitive area to detect the coils, which increase the accuracy to determine the location of the electromagnetic reflector.

A binding material for binding a bale of crop material has bale identification tags used to identify properties of the bale that is bound by the binding material. The binding material includes at least one strand of a non-identifying filament and one strand of an identifying filament incorporating the identification tags, wherein the identifying filament is formed as a continuous identification element comprising a resonant material incorporated into the identifying filament during a production process.

A wireless sensor circuit and sensor tag in which the output is directly converted to a frequency response. The sensor circuit includes a buffer transistor having gate, source and drain terminals configured as a source-follower, a gate resistor connected to the gate terminal of the buffer transistor, a supply voltage connected to the drain terminal of the buffer transistor, and an active load element and a capacitive load element connected to the source terminal of the buffer transistor. An input signal having an input frequency is applied to the buffer transistor via the gate resistor and an output signal is generated at the source terminal of the buffer transistor. The output frequency represents a response of the sensor circuit.

The system performs communication between two systems, a master system, that creates an alternating magnetic field by means of which it dialogues with one or more slave systems, which respond at frequencies other than those generated by the master by a non-linear magnetic core generating harmonics of higher order than those of the magnetic field created by the master. The generation of harmonics is controlled by the slave by a short-circuit coil which enables the data transmission from the slave to the master. The slave system can have its own power supply or it can be powered by the short-circuit coil. This allows microcontrollers in the slaves to be powered and give them intelligence and a large storage capacity, making them ideal for control security and monitoring processes. The excitation frequency can be varied because the functionality of the slaves does not depend on the frequency of the exciter field.

Inductive identification systems and methods are described. The system may include an inductive detector configured to identify objects having inductive identifiers. An inductive detector may include conductive coils and inductance readout circuitry for measuring an inductance of each coil. An inductive identifier may include a conductive pattern configured to induce a desired inductance in the coils of the inductive detector. An inductive identifier may include a film having openings, each opening configured to be disposed over a corresponding coil to induce differing inductance changes in the corresponding coils. A pattern of inductance values may be determined and used to identify the object. The detector may be implemented in a cassette recess of an infusion pump system. The inductive identifier may be disposed on a pump cassette configured to be received in the cassette recess and identified based on an inductive interaction between the inductive detector coils and the inductive identifier.