The present invention relates to a radio frequency filter employing a notch structure, wherein the notch structure is a dual notch structure which comprises: a C notch structure formed in a predetermined region at a partition between two cavities to be cross-coupled; and an L notch structure formed together with the C notch structure in a predetermined region at a partition between two cavities.

Multiple-pole resonator filter. In some embodiments, a filter for radio-frequency application can include a first coaxial resonator in a first orientation and having an input on a first side of the filter defined by N coaxial resonators, and an N-th coaxial resonator in the first orientation and having an output on the first side of the filter. The filter can further include a second coaxial resonator in a second orientation opposite the first orientation to form a first interdigitation with the first coaxial resonator, and an (N−1)th coaxial resonator in the second orientation to form a second interdigitation with the N-th coaxial resonator. The filter can further include one or more coaxial resonators coupled between the second and (N−1)th coaxial resonators, such that the N coaxial resonators have slot coupling between adjacent ones of the N coaxial resonators.

Filter devices are provided herein. In some embodiments, a filter device includes first and second resonator stalks in respective first and second openings in a PCB that has first and second metal resonator heads that are on the first and second resonator stalks, respectively. Moreover, in some embodiments, a filter device includes a metal resonator head that has a loop portion on a resonator stalk and a plurality of arms that extend outward from the loop portion.

An exemplary semiconductor technology implemented microwave filter includes a dielectric substrate with metal traces on one surface that function as frequency selective circuits and reference ground. A top enclosure encloses the substrate have respective interior recesses with deposited continuous metal coatings. A plurality of metal bonding bumps or bonding wall extends outwardly from the projecting walls of the bottom and top enclosures. The bonding bumps on the top enclosure engage reference ground metal traces on respective surface of the substrate. As a result of applied pressure, the bonding bumps and respective reference ground metal traces together with the through-substrate vias form a metal-to-metal singly-connected ground reference structure for the entire circuitry.

A multilayered filter device includes a multilayer stack, a band pass filter, a first band elimination filter, and a second band elimination filter. The band pass filter and the first and second band elimination filters are each constructed using the multilayer stack. The band pass filter includes a plurality of first resonators with open ends. Each band elimination filter includes a connection path, and a second resonator coupled to the connection path. The connection path includes an impedance transformer. The second resonator includes a conductor line constituting a distributed constant line.

This application provides an example dielectric filter and an example communications device. The dielectric filter includes a dielectric block. At least two resonant through holes that are parallel to each other are provided in the dielectric block. The resonant through hole is a stepped hole. The stepped hole includes a large stepped hole and a small stepped hole that are arranged coaxially and that are in communication. The small stepped hole passes through a first surface of the dielectric block. The large stepped hole passes through a second surface of the dielectric block. A stepped surface is formed between the large stepped hole and the small stepped hole. The surfaces of the dielectric block are covered with conductor layers. The conductor layers cover the surfaces of the dielectric block and inner walls of the large stepped hole and the small stepped hole. A conductor layer of the inner wall of the large stepped hole is short-circuited with a conductor layer of the second surface. A conductor layer of the inner wall of the small stepped hole is short-circuited with a conductor layer of the first surface. A loop gap that does not cover the conductor layers is provided on the stepped surface. The loop gap is arranged around the small stepped hole.

Disclosed herein are IC structures, packages, and devices that include III-N transistors integrated on the same substrate or die as resonators of RF filters. An example IC structure includes a support structure (e.g., a substrate), a resonator, provided over a first portion of the support structure, and an III-N transistor, provided over a second portion of the support structure. The IC structure includes a piezoelectric material so that first and second electrodes of the resonator enclose a first portion of the piezoelectric material, while a second portion of the piezoelectric material is enclosed between the channel material of the III-N transistor and the support structure. In this manner, one or more resonators of an RF filter may be monolithically integrated with one or more III-N transistors. Such integration may reduce costs and improve performance by reducing RF losses incurred when power is routed off chip.

Disclosed is a cavity filter including a housing, and a first sheet-shaped resonant rod, a second sheet-shaped resonant rod, and a third sheet-shaped resonant rod disposed in the housing. The first sheet-shaped resonant rod includes a first upright section and a first extension section extending from one side of the first upright section. The second sheet-shaped resonant rod includes a second upright section and a second extension section extending from one side of the second upright section. The second upright section, the first upright section, and the third sheet-shaped resonant rod are connected to the housing, and the first extension section and the second extension section extend toward each other. Capacitive coupling is formed between the first and second sheet-shaped resonant rods. Capacitive coupling or inductive coupling is formed between the second and third sheet-shaped resonant rods and between the first and third sheet-shaped resonant rods.

The disclosure provides a filtering module for a cavity filter having a housing defining an enclosed cavity, wherein a surface of the cavity is electromagnetically conductive; and a plurality of planar resonators arranged within the cavity, one or more of the resonators being rotatable about an axis of rotation so as to vary an electric-field coupling between the resonator and other resonators of the plurality of resonators. The disclosure also provides a cavity filter having an input for receiving a signal to be filtered; a plurality of filtering modules, each filtering module comprising: a cavity, wherein a surface of the cavity is electromagnetically conductive; and a plurality of resonators arranged within the cavity, at least one of the resonators being movable so as to vary an electromagnetic coupling between the resonator and other resonators of the plurality of resonators; and an output for outputting a filtered signal.

The disclosure provides a filtering module for a cavity filter having a housing defining an enclosed cavity, wherein a surface of the cavity is electromagnetically conductive; and a plurality of planar resonators arranged within the cavity, one or more of the resonators being rotatable about an axis of rotation so as to vary an electric-field coupling between the resonator and other resonators of the plurality of resonators. The disclosure also provides a cavity filter having an input for receiving a signal to be filtered; a plurality of filtering modules, each filtering module comprising: a cavity, wherein a surface of the cavity is electromagnetically conductive; and a plurality of resonators arranged within the cavity, at least one of the resonators being movable so as to vary an electromagnetic coupling between the resonator and other resonators of the plurality of resonators; and an output for outputting a filtered signal.