The present application provides a dielectric resonator, a dielectric filter, a base station and a method for fabricating the dielectric resonator or the dielectric filter. 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.

A dielectric thin film containing MgO as a main component, wherein the dielectric thin film is composed of a columnar structure group containing at least one columnar structure A constructed by single crystal and at least one columnar structure B constructed by polycrystal, respectively, and in the cross section of the direction perpendicular to the dielectric thin film, when the area occupied by the columnar structure A is set as C.sub.A and the area occupied by the columnar structure B is set as C.sub.B, the relationship between C.sub.A and C.sub.B satisfies 0.4≦C.sub.B/C.sub.A≦1.1.

A dielectric thin film containing MgO as a main component, wherein the dielectric thin film is composed of a columnar structure group containing at least one columnar structure A constructed by single crystal and at least one columnar structure B constructed by polycrystal, respectively, and in the cross section of the direction perpendicular to the dielectric thin film, when the area occupied by the columnar structure A is set as C.sub.A and the area occupied by the columnar structure B is set as C.sub.B, the relationship between C.sub.A and C.sub.B satisfies 0.4≦C.sub.B/C.sub.A≦1.1.

Difficulties in grounding a non-integral, deep drawn resonator (DDR) to the filter body of a cavity may be substantially eliminated by preventing the movement of the DDR away from a grounding contact area on the filter body. The addition of a compression plate and stop limiter in the connection of the non-integral DR to the filter body helps insure that any such movement is eliminated or substantially reduced.

A profile-reduced or size-reduced filter is to be provided. The filter includes: a metallic casing, an opening provided in the metallic casing, a metallic cover configured to cover the opening, and a TM mode dielectric resonator disposed in the opening and configured to electrically contact a bottom surface of the metallic casing, and the metallic cover. The TM mode dielectric resonator has a height lower than a lowest possible height at which a ¼ wavelength semi-coaxial resonator is disposed in the opening.

A profile-reduced or size-reduced filter is to be provided. The filter includes: a metallic casing, an opening provided in the metallic casing, a metallic cover configured to cover the opening, and a TM mode dielectric resonator disposed in the opening and configured to electrically contact a bottom surface of the metallic casing, and the metallic cover. The TM mode dielectric resonator has a height lower than a lowest possible height at which a ¼ wavelength semi-coaxial resonator is disposed in the opening.

A rod-switched tunable resonator includes a housing defining a cavity, a first rod disposed within the cavity, a second rod disposed within the cavity, and a switch connected to the first rod and to the second rod to tune the resonator to one of a plurality of frequencies by connecting or disconnecting one or both of the first and second rods to the housing. A tunable filter may be fabricated using two or more such resonators. The rod-switched tunable resonator may be a combline resonator, coaxial resonator, waveguide resonator, or dielectric resonator.

A high-frequency transmission device includes first and second resonators as ring-shaped wires each having an opening part at a part thereof, first and second input/output terminals each electrically connected to both resonators, a first ground shield formed on a plane different from planes on which both resonators are arranged, a second ground shield formed on a plane different from the planes on which both resonators and the first ground shield are arranged, and first and second ground wires each formed to surround peripheries of both resonators. The ground shields and the ground wires are respectively connected to each other. A dielectric wire is present between both ground wires, and the ground wires are not electrically connected to each other.

A band stop filter can include a circuit board having a first surface and an opposing second surface. The circuit board can have a transmission line on the first surface. The band stop filter can include a dielectric cavity resonator physically coupled to the second surface of the circuit board. The dielectric cavity resonator can have a coupling aperture configured to magnetically couple the dielectric cavity resonator to the transmission line, and to cause excitation of the dielectric cavity resonator in a second order transverse electric (TE) mode.

A frequency variable filter includes variable resonators aligned in a predetermined direction, a coupling part configured to couple the adjacent variable resonators, and a coupling variable dielectric. The variable resonator includes a resonator and a frequency variable dielectric disposed in a movable state relative to the resonator, and is configured to be able to change a resonance frequency according to a position of the frequency variable dielectric with respect to the resonator. This applies to aligned variable resonators other than this variable resonator. The coupling variable dielectric is disposed in a movable state with respect to the coupling part and configured to adjust a coupling coefficient according to an amount of insertion into the coupling part. The coupling variable dielectric is disposed so that a movable surface of the coupling variable dielectric is on the same plane as a movable surface of the frequency variable dielectric.