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 power line communication device including a current path provided between a first terminal and a second terminal. A coupling circuit includes a first circuit of a first inductor connected in parallel with a first capacitor and a first resistor, wherein the coupling circuit is connected between the first and second terminals. A sensor is configured to sense a communication parameter of the coupling circuit. The communication parameter may be a resonance of the first circuit, the quality (Q) factor of the resonance, the bandwidth (BW) of the coupling circuit, the resistance of the first resistor, or the impedance of the first circuit. A transceiver is adapted to couple to the first and second terminal to transmit a signal onto the current path or receive a signal from the current path responsive to the parameter of the coupling circuit and a level of current in the current path sensed by the sensor.

A varainductor includes a signal line, a ground plane, and a floating plane over a substrate. The ground plane is disposed on a side of the signal line, and the first floating plane is disposed between the ground plane and the signal line. An array of switches includes at least two switches configured to selectively electrically connect the ground plane to the floating plane.

A wireless sensor includes a radio frequency (RF) receiving circuit operable to receive an RF signal having a carrier frequency of a plurality of carrier frequencies. The RF receiving circuit further includes a variable impedance where impedance of the variable impedance is a factor in establishing a resonant frequency of the RF receiving circuit. The wireless sensor further includes a processing module that is operable to determine a first value for a first impedance of the variable impedance for a known temperature based on the resonant frequency and the carrier frequency, determine a second value a second impedance of the variable impedance for an unknown temperature based on the resonant frequency and the carrier frequency, and determine a difference between the first and second values that corresponds to a change between the known temperature and the unknown temperature.

A wireless sensor includes a radio frequency (RF) receiving circuit operable to receive an RF signal having a carrier frequency of a plurality of carrier frequencies. The RF receiving circuit further includes a variable impedance where impedance of the variable impedance is a factor in establishing a resonant frequency of the RF receiving circuit. The wireless sensor further includes a processing module that is operable to determine a first value for a first impedance of the variable impedance for a known temperature based on the resonant frequency and the carrier frequency, determine a second value a second impedance of the variable impedance for an unknown temperature based on the resonant frequency and the carrier frequency, and determine a difference between the first and second values that corresponds to a change between the known temperature and the unknown temperature.

A method includes a computing device transmitting a radio frequency (RF) signal to a passive wireless sensor. The RF signal includes a carrier frequency signal and a modulated sense request signal. The method further includes, in response to the modulated sense request signal, receiving, by the computing device, a response RF signal that includes the carrier frequency signal and a coded sense response signal from the passive wireless sensor. The coded sense response signal is representative of a sensed environmental condition by the passive wireless sensor. The method further includes generating, by the computing device, an environmental condition value based on the coded sense response signal and an environmental conversion information.

A method includes a computing device transmitting a radio frequency (RF) signal to a passive wireless sensor. The RF signal includes a carrier frequency signal and a modulated sense request signal. The method further includes, in response to the modulated sense request signal, receiving, by the computing device, a response RF signal that includes the carrier frequency signal and a coded sense response signal from the passive wireless sensor. The coded sense response signal is representative of a sensed environmental condition by the passive wireless sensor. The method further includes generating, by the computing device, an environmental condition value based on the coded sense response signal and an environmental conversion information.

Biomedical implants in accordance with various embodiments of the invention can be implemented in many different ways. The implants can be configured to receive power and transmit data, both wirelessly and simultaneously. Such devices can be configured to receive power from an external source and transmit data, such as but not limited to recorded neural data and/or other biological data, to outside the body. In many cases, the data is transmitted to the device that delivers power to the implant. For example, the power and data transmission system can be implemented with a pair of transceivers. The implant transceiver can receive power wirelessly though an external transceiver while simultaneously transmitting data to the external transceiver. In several embodiments, both forward (power) and reverse (data) links use the same pair of inductive coils in the transceivers, one coil mounted in the implant and the other in the external unit.

An augmented reality system including a source and a contact lens display can be used to project information from the contact lens display onto the retina of the wearer's eye. The source provides energy to the contact lens display and operates at a source frequency. The source includes a source circuit including a conductive coil. The contact lens display includes a resonant circuit including another conductive coil and a capacitive circuit. The resonant circuit receives energy from the conductive coil of the source via a magnetic field inductively coupling the conductive coils. The contact lens display additionally includes a feedback circuit to adjust the capacitance of the capacitive circuit to control a resonant frequency of the resonant circuit. The feedback circuit can control the capacitive circuit to maintain the resonant frequency of the resonant circuit near the source frequency as the wearer's eye blinks.

A method includes sending, by a reader, a radio frequency (RF) signal to a wireless sensor that includes an antenna having a tail section and a head section. The tail section is for placement in an RF limited area for sensing moisture in a first location of a vehicle under test and wherein the head section is for placement in a non-RF limited area. The method further includes receiving, by the reader, an RF response to the RF signal from the wireless sensor. The first RF response includes an indication of adjustment of one or more RF characteristics of the wireless sensor, which corresponds to a variance of the one or more RF characteristics from a desired value, which, in turn, corresponds to a level of moisture at the first location. The method further includes outputting, by the reader, a message regarding the level of moisture at the first location.