Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.

Devices and methods for improving voltage handling and/or bi-directionality of stacks of elements when connected between terminals are described. Such devices and method include use of symmetrical compensation capacitances, symmetrical series capacitors, or symmetrical sizing of the elements of the stack.

A communication system includes a passive wireless sensor and a sensor computing device. The passive wireless sensor is operable to receive a radio frequency (RF) signal including a carrier frequency signal and a modulated sense request signal, generate a power supply voltage, determine received signal strength (RSSI) of the RF signal, and determine whether the RSSI is at a desired level. When the RSSI is at a desired level, the passive wireless sensor generates a response RF signal including the carrier frequency and a coded sense response signal representative of a sensed environmental condition. The sensed environmental condition affects impedance of a front-end of the passive wireless sensor to produce an affected impedance. The passive wireless sensor generates the coded sense response signal based on tuning the affected impedance to resonate with the carrier frequency signal. The computing device operable to: transmit the RF signal, receive the response RF signal, and generate an environmental condition value based on the coded sense response signal and environmental conversion information.

A communication system includes a passive wireless sensor and a sensor computing device. The passive wireless sensor is operable to receive a radio frequency (RF) signal including a carrier frequency signal and a modulated sense request signal, generate a power supply voltage, determine received signal strength (RSSI) of the RF signal, and determine whether the RSSI is at a desired level. When the RSSI is at a desired level, the passive wireless sensor generates a response RF signal including the carrier frequency and a coded sense response signal representative of a sensed environmental condition. The sensed environmental condition affects impedance of a front-end of the passive wireless sensor to produce an affected impedance. The passive wireless sensor generates the coded sense response signal based on tuning the affected impedance to resonate with the carrier frequency signal. The computing device operable to: transmit the RF signal, receive the response RF signal, and generate an environmental condition value based on the coded sense response signal and environmental conversion information.

An apparatus and method for implementing a compact and tunable microwave resonator using NbN kinetic inductance, comprising: a DC source, an attenuator, an oxygen-free copper cavity, a superconducting coil, a first-stage amplifier, a second-stage amplifier, a vector network analyzer and a control computer, a small-sized tunable resonator whose size is reduced by 10-20 times as compared with an ordinary thin film microwave resonator is implemented in a microwave frequency band by using high kinetic inductance of an ultra-thin NbN thin film in a superconducting state, the tunability of the resonator lies in that the ultra-thin NbN thin film serves as the LC resonance circuit, a dc-SQUID is connected to the end of the resonator, and a change in the external magnetic field causes a change in the equivalent inductance of the dc-SQUID, thereby changing the total inductance of the resonator and modulating the resonant frequency of the resonance circuit.

A low noise amplifier that may include a first input port, a second input port, a first capacitor, a second capacitor, a first variable capacitor, a second variable capacitor, an inductor, a bias circuit, a tuning circuit, a first output circuit having a first output, a second output circuit having a second output; wherein the first input port is electrically coupled to a first end of the second variable capacitor, to a first end of the first capacitor, to an input of the first output circuit, and to a first port of the inductor; wherein the second input port is electrically coupled to a second end of the first variable capacitor, to a second end of the second capacitor, to an input of the second output circuit, and to a second port of the inductor; wherein a first port of the first varactor is electrically coupled to a second end of the first capacitor; wherein a second port of the second varactor is electrically coupled to a first end of the second capacitor; wherein the bias circuit is configured to supply a bias voltage to a third port of the inductor; and wherein the tuning circuit is configured to control a capacitance of the first varactor and a capacitance of the variable capacitor.

A method includes transmitting, by a radio frequency identification (RFID) reader, a series of RF signals to a plurality of RF receiver circuits in a time sequence. The first RF signal commands the plurality of RF receiver circuits to remain silent when received signal strength of the first RF signal corresponds to a power level greater than a first power level. The method further includes receiving one or more sets of responses from one or more sets of RF receiver circuits of the plurality of RF receiver circuits in response to the series of RF signals. The method further includes determining an area of interest based on the one or more sets of responses, determining a set of power levels corresponding to the area of interest, and transmitting a second series of RF signals to the plurality of RF receiver circuits in a second time sequence.

A method includes transmitting, by a radio frequency identification (RFID) reader, a series of RF signals to a plurality of RF receiver circuits in a time sequence. The first RF signal commands the plurality of RF receiver circuits to remain silent when received signal strength of the first RF signal corresponds to a power level greater than a first power level. The method further includes receiving one or more sets of responses from one or more sets of RF receiver circuits of the plurality of RF receiver circuits in response to the series of RF signals. The method further includes determining an area of interest based on the one or more sets of responses, determining a set of power levels corresponding to the area of interest, and transmitting a second series of RF signals to the plurality of RF receiver circuits in a second time sequence.

A resonator element for use in a filter is provided. The resonator element includes a first resonator acoustically coupled to a second or third resonator or both. The first resonator has terminals for incorporation in a filter structure. A tuning circuit is coupled to the second or third resonator or both to enable tuning of the resonator element. The tuning circuit includes a variable capacitor and an inductor.

A resonator element for use in a filter is provided. The resonator element includes a first resonator acoustically coupled to a second or third resonator or both. The first resonator has terminals for incorporation in a filter structure. A tuning circuit is coupled to the second or third resonator or both to enable tuning of the resonator element. The tuning circuit includes a variable capacitor and an inductor.