Disclosed herein are printed circuit boards with at least one signal trace situated over or under a reference plane. The reference plane includes a broadband common-mode filter that comprises looping and parallel structures etched into the reference plane. The looping structure includes an even number of side arms, and the parallel structure comprises an even number of interior arms, wherein each of the side arms extends toward the parallel structure, and each of the interior arms extends toward the looping structure. The at least one signal trace is substantially parallel to the side arms and to the interior arms, and is situated between a first half of the even number of side arms and a second half of the even number of side arms and between a first half of the even number of interior arms and a second half of the even number of interior arms.

A filter is disposed on a base board. The filter includes a first portion, a second portion, a ground portion, a first coupling portion and a second coupling portion. The first portion is disposed on a first layer in the base board to input signals. The second portion is disposed on the first layer to output signals. The ground portion is disposed on a second layer in the base board. The first coupling portion is disposed on the first layer. The first coupling portion is electrically coupled to the first portion and the second portion. The first coupling portion is electrically coupled to the ground portion through via holes. The second coupling portion is disposed on the first layer. The second coupling portion is electrically coupled to the first portion and the second portion. The second coupling portion is electrically coupled to the ground portion through the via holes.

Disclosed herein are printed circuit boards (PCBs) with patterned ground structure filters and data storage devices comprising such PCBs. Each PCB comprises a resonator having an L-shape or a zig-zag shape in a plane of the printed circuit board and at least one signal trace. The resonator has a first dimension and a second dimension in the plane of the printed circuit board. A portion of the at least one signal trace is situated over the resonator and is separated by a distance from the resonator by a dielectric material. In some embodiments, at least part of the portion of the at least one signal trace extends in a same direction as the first dimension (in the case of an L-shaped resonator) or tracks the zig-zag shape of the resonator (in the case of a zig-zag-shaped resonator).

Disclosed herein are printed circuit boards with at least one signal trace situated over or under a reference plane. The reference plane includes a broadband common-mode filter that comprises looping and parallel structures etched into the reference plane. The looping structure includes an even number of side arms, and the parallel structure comprises an even number of interior arms, wherein each of the side arms extends toward the parallel structure, and each of the interior arms extends toward the looping structure. The at least one signal trace is substantially parallel to the side arms and to the interior arms, and is situated between a first half of the even number of side arms and a second half of the even number of side arms and between a first half of the even number of interior arms and a second half of the even number of interior arms.

An object is to provide a stepped impedance resonator capable of efficiently reducing a footprint. A resonator includes a coplanar waveguide and a section. The coplanar waveguide has a first impedance. The section has a second impedance different from the first impedance and includes a fishbone waveguide. The resonator is configured as a stepped impedance resonator in which the coplanar waveguide and the section including the fishbone waveguide are connected in series.

A filter is disposed on a base board. The filter includes a first portion, a second portion, a ground portion, a first coupling portion and a second coupling portion. The first portion is disposed on a first layer in the base board to input signals. The second portion is disposed on the first layer to output signals. The ground portion is disposed on a second layer in the base board. The first coupling portion is disposed on the first layer. The first coupling portion is electrically coupled to the first portion and the second portion. The first coupling portion is electrically coupled to the ground portion through via holes. The second coupling portion is disposed on the first layer. The second coupling portion is electrically coupled to the first portion and the second portion. The second coupling portion is electrically coupled to the ground portion through the via holes.

A filter is provided, and the filter includes two mutually coupled slow-wave resonators. Each resonator includes a coplanar waveguide (CPW) transmission line, a tapered CPW transmission line, and a ground stub, and can generate a slow-wave feature to push a high-order harmonic wave of a baseband signal to a high frequency, so as to implement a wide stopband feature. In addition, a slow-wave effect is used to properly design a size of a filter, to reduce an entire area of the filter and reduce costs. Moreover, two resonators are coupled, to enhance passband performance of the filter, increase bandwidth, increase in-passband flatness, and reduce an insertion loss.

In a general aspect, a microwave quantum circuit includes an on-chip impedance matching circuit. In some cases, a microwave quantum circuit includes a dielectric substrate, a quantum circuit device on the substrate, and an impedance matching circuit device on the substrate. The quantum circuit device includes a Josephson junction, and the impedance matching circuit device is coupled to the quantum circuit device on the substrate.

A flat cable high-frequency filter includes a dielectric substrate extending in a transmission direction of a high-frequency signal. The dielectric substrate includes dielectric layers stacked on each other. Elongated conductor patterns are provided on a flat surface of one dielectric layer which faces another dielectric layer. The conductor patterns are as wide as possible in the dielectric substrate in accordance with a desired inductance. A capacitive coupling conductor pattern opposes one conductor pattern by a predetermined area with a dielectric layer therebetween. By using a connecting conductor, the capacitive coupling conductor pattern is connected to the conductor pattern which does not oppose the capacitive coupling conductor pattern.

In some aspects, a quantum information processing circuit includes a lumped-element device on the surface of a dielectric substrate. The lumped-element device can include a capacitor pad and an inductive transmission line. The capacitor pad can be capacitively coupled to another capacitor pad. The inductive transmission line can reside in an interior clearance area defined by an inner boundary of the capacitor pad. The lumped-element device can be, for example, a resonator device or a filter device. The inductive transmission line can be, for example, a meander inductor.