Embodiments of the invention provide a resonant circuit including an active material substrate excitable by photon energy. A busline having a single input and a single output is located on the active material substrate. A RF resonator geometry is located on the active material substrate in electrical communication with the busline. Application of photon energy to the active material substrate changes the resonance of the RF resonator geometry at room temperatures. Alternately, a resonant circuit is provided that include a passive material substrate. An active material thin film is located on the passive material substrate. A busline having a single input and a single output and a RF resonator geometry located on the active material thin film. The RF resonator geometry is in electrical communication with the busline. Application of photon energy to the active material thin film changes the resonance of the RF resonator geometry at room temperatures.

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.

Embodiments provide a filtering device, to effectively simplify assembly and tuning processes. The filtering device includes: a housing, including an inner cavity; a resonant conductor, having a resonance function, and disposed inside the inner cavity; and a pressing element, having one end disposed on the housing and another end suspended, and facing a position of an open-circuit end of the resonant conductor. A distance between the pressing element and the resonant conductor is changeable when the pressing element is pressed or drawn to adjust a resonant frequency. The filtering device provided in various embodiments is applicable to a plurality of communications devices for selecting a signal frequency.

A resonator for spin waves, wherein the resonator comprises a stack of material layers arranged on a substrate, a waveguide structure formed in at least one material layer in the stack and configured to propagate a spin wave and to confine a spin wave propagating in a waveguide element of the waveguide structure, such that a spin wave of a selected frequency propagating in the waveguide structure is arranged to resonate in the waveguide structure. The resonator further comprises a control mechanism formed in at least one material layer in the stack and configured to adapt at least one property of the waveguide structure for tuning the resonance frequency of the waveguide structure.

A re-configurable magnetoinductive waveguide (300), comprising a plurality of resonator cells, wherein each resonator cell comprises a primary resonator (110) that is inductively coupled to a primary resonator (110) of at least one other resonator cell, and wherein at least one of the plurality of resonator cells is a controllable cell (100) which further comprises a control element (120), the control element (120) having an active control component (125) that is operable to adjust the impedance of the primary resonator (110) of the controllable cell (100) in response to a control signal; wherein: the control element (120) comprises a secondary resonator, the secondary resonator is inductively coupled to the primary resonator (110), and the active control component (125) is arranged to vary the electrical properties of the secondary resonator in response to the control signal.

The present invention provides filter assemblies, tuning elements and a method of tuning a filter. A filter assembly includes a housing having a top cover, a bottom cover and at least one sidewall, the top cover, the bottom cover and the at least one sidewall defining an internal cavity, the housing configured to receive first through third radio frequency (RF) transmission lines; a top metal sheet mounted within the internal cavity that has a plurality of openings that form a first hole pattern; and a bottom metal sheet mounted within the internal cavity that has a plurality of openings that form a second hole pattern. The top and bottom metal sheets are vertically spaced-apart from each other in a vertically stacked relationship within the internal cavity. The top metal sheet and the bottom metal sheet each include at least one resonator.

A reflective microstrip tuning circuit that operatively couples to another circuit to be tuned, in which tuning circuit receives an incident signal from the other circuit and enables adjustment of the amplitude and/or phase of the return signal reflected by the tuning circuit for use in the other circuit. The tuning circuit includes one or more cascaded couplers that divide power from the incident signal unequally among a plurality of adjustable tuning arms, in which the tuning arms may be individually adjusted to change the phase of the signal that is reflected by each arm so that both the amplitude and phase of the signal returned by the tuning circuit is adjusted to achieve the desired tuning result. The difference in the power that is divided among the tuning arms provides a progressive weighting to the adjustment effect of each tuning arm, which provides for a series of coarse through fine adjustments that enables a greater degree of resolution when tuning.

A superconducting coupling device includes a resonator structure. The resonator structure has a first end configured to be coupled to a first device and a second end configured to be coupled to a second device. A gate is positioned proximal to a portion of the resonator structure. The gate is configured to receive a gate voltage and vary a kinetic inductance of the portion of the resonator based upon the gate voltage. The varying of the kinetic inductance induces the resonator structure to vary a strength of coupling between the first superconducting device and the second superconducting device.

Provided is a dual-band resonator which can be downsized further than conventional ones. A dual-band resonator is provided with a first conductor and a second conductor. The first conductor is configured to be folded at a first folding part at the center so that both extensions are in a prescribed direction and adjacent to one another with a prescribed space therebetween, wherein a conductor part closer to one end side than the first folding part and a conductor part closer to the other end side than the first folding part are further folded at second folding parts between the one end and the first folding part and between the other end and the first folding part, respectively, in a direction in which the one end and the other end are apart from each other. The second conductor extends in a prescribed direction contiguously to the first folding part of the first conductor. The first conductor constitutes a half-wavelength resonator, and odd-mode resonance occurs in the first conductor. The first conductor and the second conductor constitute a half-wavelength resonator, and even-mode resonance occurs in the first conductor and the second conductor.

In described examples, a radio frequency (RF) resonator including a cavity and a tuning component, where the cavity includes a resonance property that can be changed in response to the tuning component. A transmitter generates an RF signal at each of a set of determined frequencies for transmitting individually within the cavity. A receiver receives the RF signal transmitted individually at each of the determined frequencies and determines a respective amplitude for each of the determined frequencies.