A method of timing a resonant frequency of a nanoelectromechanical systems (NEMS) drum device is performed by applying a gate voltage between the drum membrane [100] and a back gate [104] to alter the resonant frequency of the membrane to a desired frequency; photoionizing the drum membrane with a laser to detune the membrane resonant frequency to a ground state frequency; and releasing the gate voltage to set the membrane to the desired resonant frequency. The method provides the basis for various applications including NEMS memory and photodetection techniques. The NEMS device may be implemented as a graphene/hBN membrane [100] suspended on a Si02 layer [102] deposited on a Si substrate [104].

A family of composite resonator devices having improved performance properties for use in electronic circuits. Each composite device includes two or more resonator electrodes on a single crystal or other resonant material. The two resonators may be connected in series or parallel, based on application requirements. The two resonators have different surface areas or some other type of asymmetry, causing the response of the composite device to have suppressed spurious modes, reduced insertion loss, or both. This is accomplished by designing the electrodes to have different frequency response curves, where the responses can be tuned and combined to reduce undesirable modes. Improvements in acceleration sensitivity and temperature sensitivity are also achieved. Both physically-applied and projected electrode types are disclosed, along with several crystal shapes. The family of composite resonator devices includes both passive and active devices, such as resonators, filters and oscillators.

A self-tuning impedance-matching microelectromechanical (MEMS) circuit, methods for making and using the same, and circuits including the same are disclosed. The MEMS circuit includes a tunable reactance element connected to a first mechanical spring, a separate tunable or fixed reactance element, and an AC signal source configured to provide an AC signal to the tunable reactance element(s). The reactance elements comprise a capacitor and an inductor. The AC signal source creates an electromagnetically energy favorable state for the tunable reactance element(s) at resonance with the AC signal. The method of making generally includes forming a first MEMS structure and a second mechanical or MEMS structure in/on a mechanical layer above an insulating substrate, and coating the first and second structures with a conductor to form a first tunable reactance element and a second tunable or fixed reactance element, as in the MEMS circuit.

A self-tuning impedance-matching microelectromechanical (MEMS) circuit, methods for making and using the same, and circuits including the same are disclosed. The MEMS circuit includes a tunable reactance element connected to a first mechanical spring, a separate tunable or fixed reactance element, and an AC signal source configured to provide an AC signal to the tunable reactance element(s). The reactance elements comprise a capacitor and an inductor. The AC signal source creates an electromagnetically energy favorable state for the tunable reactance element(s) at resonance with the AC signal. The method of making generally includes forming a first MEMS structure and a second mechanical or MEMS structure in/on a mechanical layer above an insulating substrate, and coating the first and second structures with a conductor to form a first tunable reactance element and a second tunable or fixed reactance element, as in the MEMS circuit.

A variable capacitance cell includes a hybrid coupler including a first port, a second port, a third port, and a fourth port. A first variable capacitance is connected to the second port. The first variable capacitance includes one or more first variable micro-electromechanical system (MEMS) capacitor. A second variable capacitance is connected to the third port. The second variable capacitance includes one or more second variable MEMS capacitors. Control signals are applied to the first and second variable capacitances to selectively change the capacitances of the first and second variable capacitances, thereby modifying a phase difference between a signal input at the first port and a signal output from the fourth port.

A drive loop circuit for a MEMS resonator. The circuit comprises a closed loop circuit to detect and amplify a signal of the MEMS resonator, a phase shifting circuit to phase shift the detected and amplified signal, and a feedback circuit to feed the detected, amplified and phase shifted signal as a feedback signal back to the MEMS resonator. The phase shifting circuit can include a low pass filter of at least 2.sup.nd order.