Abstract: Apparatus and systems may include integrated circuits for use with Radio Frequency Identification (RFID) tags having an antenna structure with at least three coupling ends. The integrated circuits may include three or more nodes corresponding respectively to the at least three coupling ends, and a modulator switch to receive a single modulator switching signal input. Methods may include those used to form and operate such circuits. Additional apparatus, systems, and methods are disclosed.

Abstract: A system and method for generating a rectified signal in a RFID tag. An alternating signal is received by the RFID tag, and a first phase of the alternating signal is coupled to a gate and to a first non-controlling terminal of a first switching transistor. The non-controlling terminal of the first switching transistor is one of a source and a drain of the first switching transistor. A first bias voltage is applied between the first non-controlling terminal and the gate of the first switching transistor and a rectified voltage is received between the first non-controlling terminal and a second non-controlling terminal of the first switching transistor.

Abstract: A system and method for generating a rectified signal in a RFID tag. An alternating signal is received by the RFID tag, and a first phase of the alternating signal is coupled to a gate and to a first non-controlling terminal of a first switching transistor. The non-controlling terminal of the first switching transistor is one of a source and a drain of the first switching transistor. A first bias voltage is applied between the first non-controlling terminal and the first gate of the first switching transistor and a rectified voltage is received between the first non-controlling terminal and a second non-controlling terminal of the first switching transistor.

Abstract: A circuit for an RFID tag has at least two RF ports for driving points of the antenna that may correspond to different RF polarizations. The RF ports may be driven by a common modulating signal, or by separate modulating signals. Further, the ports may be coupled and uncoupled together, responsive to a control signal. The control signal may be the same as one or both of the modulating signals.

Abstract: Circuits, devices and methods for use in RFID tags include receiving multiple RF signals from multiple ports. The signals are added after some processing, to produce a single combined signal. Additional components process the single combined signal by itself.

Abstract: Circuits, devices and methods for use in RFID tags include receiving multiple RF signals from multiple ports. The signals are added after some processing, to produce a single combined signal. Additional components process the single combined signal by itself.

Abstract: A Radio Frequency IDentification (RFID) circuit for use in an RFID tag includes a FET semiconductor device that is coupled to antenna connections. The device can be part of a modulator, a demodulator, or a rectifier. A designated region for a first terminal (such as a drain or a source) is formed as an island completely surrounded by a gate structure, which minimizes parasitic effects. One or more designated regions for a second terminal (such as a source or a drain) outside the gate structure complete the FET device.

Abstract: Analog-valued floating-gate transistors are used as trimmable circuit components for modifying and/or controlling the gain, phase, offset, frequency response, current consumption, and/or transfer function of signal pathways in parallel and/or serial processing circuits in radio frequency, analog, or mixed-signal integrated circuits.

Abstract: Methods and circuits for using measurement based threshold(s) to detect Radio Frequency IDentification (RID) tag responses in readers are described. Tag response itself is detected based on a measurement that is compared to a measurement during a tag silent period. Beginning and/or end of tag response are also detected using multiple measurements during tag response. The initial detection threshold may be replaced with a lower second threshold once demodulation of the tag response begins.

Abstract: RFID reader antennas and methods for generating magnetic fields. An antenna can be made from conductors that do not contact each other, but have loop portions spatially arranged along a loop section. The loop portions have gaps between them, and thus the loop section is discontinuous. The loop section can be driven from near its ends by a UHF RFID excitation signal, which travels through the loop portions, and also through the gaps because it is AC. Thus an excitation current becomes established along the loop section, which generates a useable magnetic field. Each loop portion can be short, so that the magnetic field it contributes will not self-cancel due to the shorter wavelength of UHF RFID. The loop section can be large independently of the wavelength, so that the magnetic field is of a size large enough to be useful for ILT in RFID.