A dielectric filter, a duplexer, and a communications device are provided. The dielectric filter includes a dielectric body, and a wideband filtering structure and a narrowband filtering structure that are disposed in the dielectric body. The wideband filtering structure includes a groove disposed on a first surface of the dielectric body and configured to adjust a frequency position of a passband of the wideband filtering structure; and at least one first resonator including a through hole penetrating the bottom of the groove and a second surface of the dielectric body; and an open loop located on a bottom surface of the groove and is disposed around an opening of the through hole. The narrowband filtering structure includes at least one second resonator including a blind hole disposed on the second surface of the dielectric body. The first surface and the second surface of the dielectric body are disposed oppositely.

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.

A dielectric filter includes a plurality of resonators, wherein each resonator included in the plurality of resonators includes a tuning hole; and at least one stepped hole for adjusting capacitive coupling, wherein the at least one stepped hole is disposed between two adjacent resonators included in the plurality of the resonators, wherein the stepped hole comprises a large hole and a small through hole at a bottom center of the large hole, wherein a first sidewall and a first annular bottom of the large hole are configured with a metal conductive layer, and wherein at least one of a second sidewall of the small through hole and a second annular portion outside a bottom of the small through hole is not covered with the conductive layer.

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.

A filter circuit may include a transmission line, a quarter wave resonator, and an electrical component coupled in series with the quarter wave resonator at a first end and to the transmission line at a second end. The electrical component may be have a frequency dependent impedance. The electrical component may be an inductor, a capacitor, or an inductor in series with a capacitor. In another aspect, a filter circuit may include a transmission line, a first quarter wave resonator coupled to a first electrical component and a second quarter wave resonator coupled to a second electrical component. Each of the first and second electrical components may be coupled to the transmission line in parallel with each other. The first and the second electrical components may have a frequency dependent impedance. The first electrical component may be the same as or different from the second electrical component.

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.

A ceramic waveguide filter comprises a plurality of resonant cavities defined by a plurality of through partition walls formed in a single ceramic block to divide sections of the ceramic block according to a pre-designated pattern, a plurality of resonant recesses formed in the sections of the plurality of resonant cavities divided by the through partition walls, a metal layer formed on an inner surface of each of the plurality of through partition walls, and input/output interfaces formed in two resonant cavities inputting and outputting signals among the plurality of resonant cavities.

Disclosed is a dielectric filter. The dielectric filter includes a body, a first resonant unit, a second resonant unit and a groove. The first resonant unit is arranged at a first side of the body. The second resonant unit is arranged at a second side of the body opposite to the first side. The groove is formed at a middle position of the body and is configured to partially separate the first resonant unit and the second resonant unit from each other. Each of the first resonant unit and the second resonant unit includes a first frequency resonant hole, a second frequency resonant hole and a coupling adjustment hole. In each of the first resonant unit and the second resonant unit, the first frequency resonant hole and the second frequency resonant hole are located on different surfaces of the body, and the first frequency resonant hole has a first longitudinal extension line perpendicular to a second longitudinal extension line of the second frequency resonant hole, and the coupling adjustment hole is located on another surface of the body and has a third longitudinal extension line parallel to the first longitudinal extension line or the second longitudinal extension line.

A dielectric resonator includes a dielectric block, an external conductor, and wall-surface conductors. The dielectric block has a rectangular parallelepiped shape including a first surface and a second surface opposed to each other. The dielectric block includes a through hole extending from the first surface to the second surface. The external conductor is disposed on an outer surface of the dielectric block. The wall-surface conductors are disposed on a wall surface defining the through hole. The wall-surface conductor includes a first portion of the through hole adjacent to the first surface and a second portion of the through hole adjacent to the second surface. The first and second portions of the wall-surface conductors are separated by a separation distance.

A dielectric filter includes a plurality of resonators, wherein each resonator included in the plurality of resonators includes a tuning hole; and at least one stepped hole for adjusting capacitive coupling, wherein the at least one stepped hole is disposed between two adjacent resonators included in the plurality of the resonators, wherein the stepped hole comprises a large hole and a small through hole at a bottom center of the large hole, wherein a first sidewall and a first annular bottom of the large hole are configured with a metal conductive layer, and wherein at least one of a second sidewall of the small through hole and a second annular portion outside a bottom of the small through hole is not covered with the conductive layer.