A method of manufacturing a ceramic resonator radio frequency filter includes placing one or more first coaxial resonators on a printed circuit board, and placing one or more second coaxial resonators over the one or more first coaxial resonators so that the coaxial resonators are arranged in a stacked configuration on the printed circuit board. The method also includes electrically connecting the one or more first coaxial resonators and second coaxial resonators to the printed circuit board.

A high frequency filter A1 has frequency characteristics such that the amount of attenuation for an input electrical signal is smaller in a first frequency band f1 than in a second frequency band f2. The high frequency filter A1 is provided with a dielectric elastomer transducer 1 that includes a dielectric elastomer layer 13 and a pair of electrode layers 14 sandwiching the dielectric elastomer layer 13. The frequency characteristics are variable by the dielectric elastomer transducer 1. This configuration provides a high frequency filter having frequency characteristics that are variable and suitable for a lightweight and compact configuration.

Disclosed is a resonant filter, which includes a housing including an input hole and an output hole, an input resonator including an input resonant body and an input port extending from the input resonant body and out of the housing through the input hole, and an output resonator including an output resonant body and an output port extending from the output resonant body and out of the housing through the output hole. The input resonator and the output resonator are fixed in the housing. The input resonator body and the output resonator body, which are sheets with a metal surface or metal sheets, respectively include a resonant rod with an upright segment, an extension segment extending from the upright segment and one end of which away from the extension segment is connected to the housing, and a first branch extending from the extension segment away from the upright segment.

An in-line resonator filter has a linear array of three or more conductors. A first pair of adjacent conductors has inductive main coupling and oppositely signed capacitive main coupling, while a second pair of non-adjacent conductors has inductive cross-coupling. The first and second pairs have one conductor in common. Between the second pair of non-adjacent conductors, there is no direct ohmic connection that provides the corresponding inductive cross-coupling. The oppositely signed capacitive main coupling compensates for at least a portion of the inductive main coupling between the first pair of adjacent conductors. The in-line resonator filter is able to provide one or more transmission zeros without requiring any discrete bypass connectors that provide direct ohmic connection between pairs of non-adjacent conductors. As such, the in-line resonator filters can be smaller, less complex, and less susceptible to damage.

An in-line resonator filter has a linear array of three or more conductors. A first pair of adjacent conductors has inductive main coupling and oppositely signed capacitive main coupling, while a second pair of non-adjacent conductors has inductive cross-coupling. The first and second pairs have one conductor in common. Between the second pair of non-adjacent conductors, there is no direct ohmic connection that provides the corresponding inductive cross-coupling. The oppositely signed capacitive main coupling compensates for at least a portion of the inductive main coupling between the first pair of adjacent conductors. The in-line resonator filter is able to provide one or more transmission zeros without requiring any discrete bypass connectors that provide direct ohmic connection between pairs of non-adjacent conductors. As such, the in-line resonator filters can be smaller, less complex, and less susceptible to damage.

This disclosure describes a dielectric filter and a communications device. In one example, the dielectric filter includes at least two dielectric resonators, a first through-hole is disposed between at least one pair of adjacent dielectric resonators, and the first through-hole is configured to cut a magnetic field between the at least one pair of adjacent dielectric resonators. In some implementations, a magnetic field distribution in the dielectric filter may be cut via the first through-hole, so that a magnetic field distribution area is reduced, and a high-order harmonic wave frequency can be increased, thereby improving a remote suppression capability and meeting the specification requirements.

A cavity device is disclosed comprising a plurality of flat boards stacked one on lop of the other to form a multilayered structure. At least some of the flat boards comprise at least one opening or perforations having one or more layers of electrically conducting materials configured to establish electrical conduction with one or more layers of electrically conducting materials of another one of the flat boards, to thereby form electrically conducting patterns in the multilayered structure for interacting with electromagnetic radiation introduced into the cavity device.

Filter devices are provided herein. A filter device includes a plurality of low-band resonators and a plurality of high-band resonators. In some embodiments, adjacent ones of the plurality of high-band resonators are spaced farther apart from each other than adjacent ones of the plurality of low-band resonators are spaced apart from each other.

Filter devices are provided herein. A filter device includes a plurality of low-band resonators and a plurality of high-band resonators. In some embodiments, adjacent ones of the plurality of high-band resonators are spaced farther apart from each other than adjacent ones of the plurality of low-band resonators are spaced apart from each other.

A filtering device includes at least one dielectric resonant element, which includes a dielectric block, an outer conductor, and an inner conductor, a terminal disposed in a through hole of the dielectric resonant element from a front surface, a plate-shaped circuit element electrically coupled with the at least one dielectric resonant element via the terminal, and a substrate on which the at last one dielectric resonant element and the plate-shaped circuit element are mounted. The outer conductor is disposed so as to cover the back surface besides the peripheral surface of the dielectric block. The first end surface of the dielectric block includes a first electrode-free portion that electrically isolates the inner conductor from the outer conductor, and a second electrode-free portion that electrically isolates the inner conductor from the outer conductor.