A directional coupler includes a main line through which a first signal in a first frequency band and a second signal in a second frequency band pass from a first port to a second port, a sub-line electromagnetically coupled to the main line and having a third port and a fourth port, the third port outputting a first coupled signal corresponding to the first signal and a second coupled signal corresponding to the second signal, a first termination circuit connected to the fourth port and used in outputting the first coupled signal, a second termination circuit connected to the fourth port and used in outputting the second coupled signal, and a first filter circuit disposed between the fourth port and the first termination circuit, wherein the first filter circuit has frequency characteristics allowing the first coupled signal to pass therethrough and attenuating the second coupled signal.

A voltage-controlled oscillator (VCO) includes a first transistor cross-coupled with a second transistor, and a transformer-coupled band-pass filter (BPF) including a first transformer and a second transformer. The first transformer is configured to control a gate and a drain terminal of the first transistor, and the second transformer is configured to control a gate and a drain terminal of the second transistor.

A memory device including a plurality of memory units; at least one geometric mean operator coupled to at least two of the plurality of memory units; and a memory state reader coupled to the at least one geometric mean operator to read a memory state of the plurality of memory units.

A tunable dual-band resonator and a tunable dual-band band-pass filter using the tunable dual-band resonator. The dual-band resonator is structured such that a stub is added to each half-wavelength resonator provided with half-wavelength resonator protrusions (capacity-component adjust parts). The dual-band resonator is made up of an odd-number mode resonator in a shape including a ground conductor disposed on the back surface of a dielectric body, and a strip conductor disposed on the top surface thereof, and an even-number mode resonator in such a shape as to be formed when the stub is connected to an end face on the opposite side of the open-end of the strip, characterized in that a dielectric rod having a circular cross section is provided in the space above the respective stubs and another dielectric rod having a circular cross section is provided in the space above the half-wavelength resonator protrusions.

Fabrication of superconducting devices that combine or separate direct currents and microwave signals is provided. A method can comprise forming a direct current circuit that supports a direct current, a microwave circuit that supports a microwave signal, and a common circuit that supports the direct current and the microwave signal. The method can also comprise operatively coupling a first end of the direct current circuit and a first end of the microwave circuit to a first end of the common circuit. The direct current circuit can comprise a bandstop circuit and the microwave circuit can comprise a capacitor. Alternatively, the direct current circuit can comprise a bandstop circuit and the microwave circuit can comprise a bandpass circuit. Alternatively, the microwave circuit can comprise a capacitor and the direct current circuit can comprise one or more quarter-wavelength transmission lines.

A filter assembly is disclosed that includes a monolithic filter having a surface and a heat sink coupled to the surface of the monolithic filter. The heat sink includes a layer of thermally conductive material that can have a thickness greater than about 0.02 mm. The heat sink may provide electrical shielding for the monolithic filter. In some embodiments, the filter assembly may include an organic dielectric material, such as liquid crystalline polymer or polyphenyl ether. In some embodiments, the filter assembly may include an additional monolithic filter.

An integrated isolator circuit for isolating receiver and transmitter in a Time-Division Duplex transceiver is disclosed. The integrated isolator circuit comprises a first node, a second node and a third node. The integrated isolator circuit further comprises a first capacitor connected in series with a first switch and connected between the first and second nodes. The integrated isolator circuit further comprises a first inductor connected between the first and second nodes and a second capacitor connected between the second node and the third node. The first switch has an on state and an off state, and the integrated isolator circuit is configured to have a different impedance at a certain operating frequency by controlling the state of the first switch.

An acoustic resonator structure is provided. The acoustic resonator structure includes an acoustic resonator configured to resonate in a resonance frequency to pass a radio frequency (RF) signal from an input node to an output node. However, the acoustic resonator may create an electrical capacitance in parallel to the acoustic resonator. The electrical capacitance may cause the acoustic resonator to resonate outside the resonance frequency, thus compromising performance of the acoustic resonator. In this regard, an active circuit is provided in parallel to the acoustic resonator in the acoustic resonator structure. The active circuit can be configured to cause a negative capacitance between the input node and the output node. As such, it may be possible to cancel the electrical capacitance created by the acoustic resonator, thus helping to improve performance of the acoustic resonator.

A band pass filter includes: a first circuit unit including a first series LC resonant circuit disposed between a first terminal and a second terminal; a second circuit unit disposed between the first circuit unit and the second terminal, and including a first parallel LC resonant circuit; and a third circuit unit disposed between the first terminal and a ground, and including a second series LC resonant circuit, wherein a resonant frequency of the first circuit unit is in a pass band.

A filter device includes a main body, a ground terminal, ground electrodes, resonators, and a via. The ground electrodes are at different positions in a normal direction of the main body. The resonators are between the ground electrodes and electromagnetically coupled to each other. Each of the resonators includes two capacitor electrodes connected by a via. When the main body is viewed in plan view, each of the capacitor electrodes overlaps a respective one of the ground electrodes. The resonators include first resonators respectively connected to an input terminal and an output terminal, and second resonators between the first resonators. The via is between the second resonators when the main body is viewed in plan view from the normal direction, and is connected to the ground electrodes.