RF co-designed bandpass filters/isolators (BPFIs) are based on series-cascaded non-reciprocal resonant stages, microwave resonators and multi-resonant cells. The non-reciprocal stages are shaped by an in-parallel cascaded transistor-based path and a transmission line (TL) that result in a zero-phase resonance in the forward direction and high isolation in the reversed one. This includes coupling routing diagrams (CRDs) of BPFs that result in low- and high-order transfer functions with and without transmission zeros in their forward direction and high levels of isolation in the reverse one. BPFIs provide alternative-type of filtering responses (e.g., flat-passband, quasi-elliptic) with and without gain in the forward direction and high levels of isolation in the reversed one. BPFIs include five planar microstrip/lumped element (LE) prototypes using hybrid combinations of non-reciprocal resonant stages, microwave resonators and multi-resonant cells.

Methods and apparatus for a frequency selective limiter (FSL) having a magnetic material substrate that tapers in thickness and supports a transmission line that has segments and bends. The segments, which differ in width and are substantially parallel to each other, such that each segment traverses the substrate on a constant thickness of the substrate.

Distributed gain equalization circuits for use with radio frequency (RF) devices are provided. The distributed gain equalization circuits include a substrate layer, multiple transverse electromagnetic (TEM) line circuits disposed on the substrate layer and multiple traces disposed on the substrate layer, each trace connected to one or more of the TEM line circuits. The traces and TEM line circuits are configured to provide resistances, inductances and capacitances to eliminate the need for lumped or packaged resistors, inductors and capacitors. The distributed gain equalization circuit operates at millimeter wave frequencies and provides a compensating gain slope to counteract a negative gain slope of the RF device. Methods of manufacturing distributed gain equalization circuits are also provided.

A reduction in size and cost of a filter capable of changing a pass band is realized. A filter includes a first distributed constant line, a first impedance element, a second impedance element, and a first switch. The first impedance element and the first switch are connected in series between the first distributed constant line and a ground point. The second impedance element is connected between the first distributed constant line and the ground point.

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.

The invention discloses a filter device. The filter device comprises a substrate, at least one transmission conductor, and a reference conductor having a slotted structure. The substrate is provided at a first surface thereof with the transmission conductor, and provided at a second surface thereof with the reference conductor. The slotted structure comprises a frame portion, a slotted portion, and a hollow portion. The slotted portion surrounds the frame portion, and the hollow portion is formed in the frame portion. At least one impedance unit is configured on the frame portion. The equivalent filter circuit of the filter device is formed between the transmission conductor, the slotted structure, the reference conductor, and the impedance unit. Thereby, the equivalent filter circuit absorbs at least one noise at at least one specific frequency by the impedance unit to avoid the noise reflected to affect the transmission quality of signal.

A semiconductor technology implemented high-frequency channelized filter includes a dielectric substrate with metal traces disposed on one of two major surfaces of the substrate. An input and output port disposed on the substrate and one of the metal traces carrying a high-frequency signal to be filtered between the input and output port. Other of the metal traces are connected to the one metal trace at intervals along the length of the one metal trace each providing a reactance to the high-frequency signal where the reactance varies with frequency and additional traces of the metal traces serving as a reference ground for the one metal trace and the other metal traces. A silicon enclosure mounted to the substrate with a first planar surface with cavities in the enclosure that extend through the first surface, and internal walls within the silicon enclosure defining the cavities. A layer of conductive metal covers the first planar surface, cavities and the internal walls. The silicon enclosure having substantially continuous areas of metal on the first planar surface about the periphery of the silicon enclosure that engage corresponding areas of the additional traces about the periphery of the substrate. The cavities surround the respective other metal traces with the internal cavity walls engaging the additional traces adjacent the respective other metal traces to individually surround each of the other metal traces with a conductive metal thereby providing electromagnetic field isolation between each of the other metal traces.

A non-common-ground bandpass filter circuit with electrostatic discharge (ESD) protection is disclosed. The non-common-ground bandpass filter circuit with ESD protection includes a non-common-ground plane, a dielectric substrate and a conductor. The conductor is disposed above the non-common-ground plane. The dielectric substrate is disposed between the conductor and the non-common-ground plane. The non-common-ground plane at least has a first ground region and a second ground region separated and insulated from each other. The first ground region corresponds to a first terminal of the conductor and the second ground region corresponds to a second terminal of the conductor. When an ESD event occurs on one of the first ground region and the second ground region, the other of the first ground region and the second ground region will not be damaged by the ESD event. The non-common-ground bandpass filter circuit also provides surge protection.

A signal transmission device including a signal wiring, a wide wiring that is formed continuously with one and the other of the signal wirings and has a wiring width larger than a wiring width of at least the one or the other of the signal wirings, a power wiring to which a signal/power separation filter is connected via a branch wiring branching from the wide wiring, and an open stub wiring that is connected to the branch wiring and has an open tip.

A laminated circuit assembly for filtering signals in one or more signal lines in, for instance, a quantum computing system is provided. In one example, the laminated circuit assembly includes one or more signal lines disposed within a substrate in a first direction. The laminated circuit assembly includes a dielectric portion of the substrate. The laminated circuit assembly includes a filter portion of the substrate extending in a first direction and containing a frequency absorbent material providing less attenuation to a first signal of a first frequency than to a second signal of a second, higher frequency. The filter portion is configured to attenuate infrared signals passing through the one or more signal lines.