Provided is a multi-resonator bandpass filter, which comprises a block, an input electrode, and an output electrode. The block comprises an open surface, a short-circuited surface, and a top surface. Multiple of resonant holes are penetrated through the block. The open surface is provided with a first hollowed-out region; the top surface is provided with two second hollowed-out region; the input electrode and the output electrode are disposed on the two second hollowed-out region, respectively. The block further comprises a ground metal layer and a resonant coating layer. Each of the resonant holes is coaxially provided with a first groove and a second groove in the direction from the open surface to the short-circuited surface. The first groove is a rectangular shape in the cross-section parallel to the open surface, and the second groove is substantially a round shape in the cross-section parallel to the open surface.

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 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.

A duplexer includes a 90 hybrid connected to an antenna terminal, a 90 hybrid connected to a terminating resistor, a transmission-side filter connected to the 90 hybrid connected to the antenna terminal, and notch filters connected to both of the 90 hybrids and mutually having the same filter characteristics, where each of the notch filters is a band elimination filter configured to reflect a radio frequency signal of a transmission band and allow a radio frequency signal of a band other than the transmission band to pass through.

An antenna filter unit and a base station having the antenna filter unit are disclosed. The antenna filter unit according to an embodiment comprises a dielectric body that defines a plurality of single-mode resonators each including a tuning hole. At least one slot is formed on a surface of the dielectric body to serve as an antenna radiator. The at least one slot is coupled to at least one of the resonators.

The present application is directed to a filter and methods of making the same. The filter includes a block of dielectric material with a top surface including a patterned region, a bottom surface, and side surfaces. The filter also includes a through-hole extending through the block from the top surface to the bottom surface. The through-hole may include a top edge that connects the top surface with an inner wall of the through hole and a bottom edge that connects the bottom surface with the inner wall of the through hole. The top edge or bottom edges of the through-hole may be rounded, chamfered, or tapered.

The application at least describes a tuning and measurement fixture. The fixture comprises a bottom plate including side surfaces, a top surface and a bottom surface. The bottom plate includes a window extending between the top and bottom surfaces. The window can expose a through-hole of a filter positioned in the fixture. In addition, the top surface of the filter includes a signal connection and a ground connection configured to communicate with the filter. The bottom surface of the filter includes an RF port configured to transmit electrical characteristics of the filter. A top plate of the filter includes a top and a bottom surface. The top plate is separated from the bottom plate by a predetermined height. The top plate includes a window extending between the top and bottom surfaces. The window exposes the through-hole of the filter held in the fixture. The application also describes a method of tuning and measuring a filter in a fixture.

A dielectric resonator, a dielectric filter, a base station and a method for fabricating the dielectric resonator or the dielectric filter are provided. The dielectric resonator includes: a solid dielectric resonator body, a blind hole located on one side of the solid dielectric resonator body, a metalized layer covering both a surface of the solid dielectric resonator body and a surface of the blind hole, and a demetallized notch located at the metalized layer on the surface of the blind hole. The dielectric resonator provided in the present application can implement tuning of the dielectric resonator, and reduce impact on the resonance frequency of the dielectric resonator after the dielectric resonator is tuned, where the impact caused by that the demetallized notch is covered by a metal material in an assembly process of the dielectric resonator, and signal energy that is leaked from the notch is reduced.

This filter comprises: a dielectric substrate; a plurality of resonators that are formed inside the dielectric substrate, and for which the periphery is surrounded by a shielding conductor; and input/output terminals that are formed at a portion at which the shielding conductor is not formed. The resonator closest to the input/output terminal of the plurality of resonators and the resonator that is closest to the input/output terminal of the plurality of resonators are in a point-symmetrical positional relationship.

The present application is directed to a filter and methods of making the same. The filter includes a block of dielectric material with a top surface including a patterned region, a bottom surface, and side surfaces. The filter also includes a through-hole extending through the block from the top surface to the bottom surface. The through-hole is partially surrounded by the patterned region, The filter also includes a wall extending from the top surface, the wall having an inner surface, an outer surface, and a roof. The bottom surface, side surfaces, outer surface, and roof have a first coating including glass frit. The patterned region, through-hole and inner surface have a second coating including glass frit. The glass frit in the first coating is at least 0.5% greater than the glass frit in the second coating. The application is also directed to a system including a printed circuit board and a filter.