A dynamic aperture is disclosed. A dynamic aperture includes a base layer, a conductive structure disposed on the base layer, and a layer of a material having a dynamically controllable electrical conductivity that is disposed over the base layer and the conductive structure. A transmission profile of the dynamic aperture is determined by a combination of the conductive structure and the layer of the material. The transmission profile is dynamically alterable by controlling the electrical conductivity of the layer of the material.

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 differential oscillator includes a differential circuit and a transformer-coupled band-pass filter (BPF) coupled between first and second output nodes. The BPF includes a coupling device coupled between the output nodes and a transformer including first and second windings in a metal layer of an IC. The first winding includes first and second conductive structures coupled to the first output node and a voltage node, respectively, and a third conductive structure including first and second extending portions connected to the first and second conductive structures, respectively. The second winding includes a fourth conductive structure including a third extending portion coupled to the voltage node and a fourth extending portion coupled to the second output node. The third extending portion is between the second conductive structure and the first extending portion, and the fourth extending portion is between the first conductive structure and the second extending portion.

An acoustic wave device includes a piezoelectric substrate made of LiNbO.sub.3, and a dielectric film provided on the piezoelectric substrate to cover first and second IDT electrodes on the piezoelectric substrate. The first and second IDT electrodes include main electrode layers. When wave lengths determined by electrode finger pitches of the first and second IDT electrodes are λ.sub.1 and λ.sub.2, respectively, the average value thereof is λ.sub.0, λ.sub.1/λ.sub.0=1+X, and λ.sub.2/λ.sub.0=1−X, a relationship of 0.05≤X≤0.65 is satisfied. The wavelength λ.sub.1 is the longest, and the wavelength λ.sub.2 is the shortest. In Euler angles (φ, θ, ψ) of the piezoelectric substrate, φ is 0°±5°, ψ is 0°±10°, and θ satisfies Expression 1, wherein a relationship of B.sub.1<T×r≤0.10λ.sub.0 and B.sub.2<T×r≤0.10λ.sub.0 are satisfied.

An analog to digital conversion circuit includes an analog to digital converter (ADC) circuit operable to convert an analog signal having an oscillation frequency into a first digital signal having a first data rate frequency. The analog signal includes a set of pure tone components. The first digital signal includes n 1-bit channels. The analog to digital conversion circuit further includes a digital decimation filtering circuit including n anti-aliasing filters operable to sample and filter the n 1-bit channels of the first digital signal to produce n second digital signals and n decimator circuits operable to decimate the n second digital signals to produce n third digital signals at a second data rate frequency. The analog to digital conversion circuit further includes a multiplexor operable to output the n third digital signals at the second data rate frequency on a single bus.

Networks and filters are disclosed. A network includes a resonator that exhibits both a resonance and an anti-resonance and an inverter circuit connected in parallel with the resonator to form a composite resonator. An anti-resonant frequency of the composite resonator is different from the resonator's anti-resonant frequency.

An antenna switch of a radio frequency module selectively switches at least between connection between a first connection terminal and a common terminal and connection between a second connection terminal and the common terminal. A first connection terminal receives a signal in a first communication band. A second connection terminal receives a signal in a second communication band. When the second connection terminal and the common terminal are in connection with each other, a variable capacitor (C1, C2) of a filter circuit shifts the attenuation band of the filter circuit to a higher band than that when the first connection terminal and the common terminal are in connection with each other.

A reflectionless frequency filter circuit is provided. The reflectionless frequency filter circuit may include a first partial circuit including a first inductor and a first resistor connected in parallel with the first inductor, a first inverter connected in parallel with the first partial circuit, and a third partial circuit connected in series with the first inverter, and the third partial circuit may include a third inductor and a third resistor formed in a branch line between the first inverter and the third inductor.

A band-pass filter includes a first input/output port, a second input/output port, a first high-pass filter, a first low-pass filter, and a first stub resonator. The first stub resonator includes a first distributed constant line. The first low-pass filter is provided between the first input/output port and the first high-pass filter in the circuit configuration. The first distributed constant line has a first end connected to a first path connecting the first input/output port and the first low-pass filter, and a second end closest to a ground in the circuit configuration.

A branching filter includes a common port, a first signal port, a second signal port, a first filter, which is provided between the common port and the first signal port, that selectively passes a signal of a frequency within a first passband, a second filter, which is provided between the common port and the second signal port, that selectively passes a signal of a frequency within a second passband different from the first passband, and a capacitor that has a first end and a second end and connects the first filter and the second filter.