A cavity resonator tuning diaphragm comprising a plurality of inner corrugations, the plurality of inner corrugations having a first depth. An outer corrugation located between the plurality of inner corrugations and a perimeter of the diaphragm is also included, the outer corrugation having a second depth greater than the first depth. The addition of the outer deep corrugation provides increased thermal stability and reduced required actuation voltage.

Exemplary embodiments relate to a control circuit (202) for a base station (204) for transmitting energy to a receiver (206) by means of an electric resonant circuit (208; 300). The control circuit (202) comprises an evaluation device (210) which is designed to compare energy that has been transmitted to a receiver resonant circuit (212) of the receiver (206) with an energy set value. The control circuit (202) is designed to alter the energy input into the receiver resonant circuit (212) of the receiver (206) by altering a resonant frequency of the resonant circuit (208; 300) on the basis of the result of the comparison.

A cavity resonator tuning diaphragm comprising a plurality of inner corrugations, the plurality of inner corrugations having a first depth. An outer corrugation located between the plurality of inner corrugations and a perimeter of the diaphragm is also included, the outer corrugation having a second depth greater than the first depth. The addition of the outer deep corrugation provides increased thermal stability and reduced required actuation voltage.

A cavity resonator tuning diaphragm comprising a plurality of inner corrugations, the plurality of inner corrugations having a first depth. An outer corrugation located between the plurality of inner corrugations and a perimeter of the diaphragm is also included, the outer corrugation having a second depth greater than the first depth. The addition of the outer deep corrugation provides increased thermal stability and reduced required actuation voltage.

Adaptive self-tunable antenna systems and methods are provided including a closed-loop system for sensing near-field RF signals of transmitted RF signals and tuning an antenna or switching between multiple antennas, so that the strength of the transmitted RF signals is maximized. A sensing antenna detects the near-field RF signal, which is filtered and converted to an RF strength control signal that can be used to generate an antenna tuning control signal. An antenna tuner uses the antenna tuning control signal to keep the antenna in resonance by dynamically changing the electrical length of the antenna or switching between multiple antennas to maximize the strength of the radiated RF signal. Such antennas may be less prone to detuning due to interaction with human bodies or other objects. Dynamically matching the antennas to an RF power amplifier and low noise amplifier can improve stability, power efficiency, gain, noise figure, and receiver sensitivity.

Adaptive self-tunable antenna systems and methods are provided including a closed-loop system for sensing near-field RF signals of transmitted RF signals and tuning an antenna or switching between multiple antennas, so that the strength of the transmitted RF signals is maximized. A sensing antenna detects the near-field RF signal, which is filtered and converted to an RF strength control signal that can be used to generate an antenna tuning control signal. An antenna tuner uses the antenna tuning control signal to keep the antenna in resonance by dynamically changing the electrical length of the antenna or switching between multiple antennas to maximize the strength of the radiated RF signal. Such antennas may be less prone to detuning due to interaction with human bodies or other objects. Dynamically matching the antennas to an RF power amplifier and low noise amplifier can improve stability, power efficiency, gain, noise figure, and receiver sensitivity.

Methods and circuitry for calibrating inductive-capacitive resonant circuits are disclosed. An example of the circuitry includes an inductive-capacitive (L-C) resonant circuit operable to receive signals in response to induced electromagnetic signals transmitted on a carrier frequency. A demodulator has a signal source and is operable to demodulate signals generated by the L-C resonant circuit. Switching circuitry is operable to inject signals generated by the signal source into the L-C resonant circuit during a calibration mode. The calibration mode is for adjusting the capacitance in the L-C resonant circuit to tune the L-C resonant circuit to the carrier frequency.

Methods and circuitry for calibrating inductive-capacitive resonant circuits are disclosed. An example of the circuitry includes an inductive-capacitive (L-C) resonant circuit operable to receive signals in response to induced electromagnetic signals transmitted on a carrier frequency. A demodulator has a signal source and is operable to demodulate signals generated by the L-C resonant circuit. Switching circuitry is operable to inject signals generated by the signal source into the L-C resonant circuit during a calibration mode. The calibration mode is for adjusting the capacitance in the L-C resonant circuit to tune the L-C resonant circuit to the carrier frequency.

An antenna having radio-frequency (RF) resonators with tunable capacitors. In one embodiment, the tunable capacitor for tuning an RF resonator comprises: a first substrate with a first electrode attached thereto; a second substrate with a second electrode attached thereto; and a membrane between the first and second electrodes, the membrane being movable between the first and second electrodes in order to change capacitance.

An antenna having radio-frequency (RF) resonators with tunable capacitors. In one embodiment, the tunable capacitor for tuning an RF resonator comprises: a first substrate with a first electrode attached thereto; a second substrate with a second electrode attached thereto; and a membrane between the first and second electrodes, the membrane being movable between the first and second electrodes in order to change capacitance.