A dielectric resonator includes a dielectric substrate, a distributed element, and a shield conductor portion. The distributed element extends in the X-axis direction inside the dielectric substrate. The shield conductor portion is on a surface of the dielectric substrate and winds around the distributed element when the distributed element is viewed from the X-axis direction in plan view. One end of the distributed element is not connected to the shield conductor portion. The distributed element includes a plurality of conductors.

Provided is a dual-band resonator which can be downsized further than conventional ones. A dual-band resonator is provided with a first conductor and a second conductor. The first conductor is configured to be folded at a first folding part at the center so that both extensions are in a prescribed direction and adjacent to one another with a prescribed space therebetween, wherein a conductor part closer to one end side than the first folding part and a conductor part closer to the other end side than the first folding part are further folded at second folding parts between the one end and the first folding part and between the other end and the first folding part, respectively, in a direction in which the one end and the other end are apart from each other. The second conductor extends in a prescribed direction contiguously to the first folding part of the first conductor. The first conductor constitutes a half-wavelength resonator, and odd-mode resonance occurs in the first conductor. The first conductor and the second conductor constitute a half-wavelength resonator, and even-mode resonance occurs in the first conductor and the second conductor.

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.

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.

Disclosed herein are embodiments of high Q, temperature stable materials with low dielectric constants. In one aspect, a low loss dielectric material includes one or more transition metal oxides based on the (Zn, Ni, Co)O—Al.sub.2O.sub.3—TiO.sub.2 system comprising an aluminate comprising one of cobalt (Co) or nickel (Ni) crystallized in a spinel structure. The low loss dielectric material additionally comprises one or more of: a titanate comprising the one of Co or Ni crystallized in a spinel structure, an aluminum oxide and a titanium oxide crystallized in a rutile structure.

Disclosed herein are embodiments of high Q, temperature stable materials with low dielectric constants. In one aspect, a low loss dielectric material includes one or more transition metal oxides based on the (Zn, Ni, Co)O—Al.sub.2O.sub.3—TiO.sub.2 system comprising an aluminate comprising one of cobalt (Co) or nickel (Ni) crystallized in a spinel structure. The low loss dielectric material additionally comprises one or more of: a titanate comprising the one of Co or Ni crystallized in a spinel structure, an aluminum oxide and a titanium oxide crystallized in a rutile structure.

A dielectric resonator antenna (DRA) includes: a volume of a dielectric material configured to be responsive to a signal feed, the signal feed being productive of a main E-field component having a defined direction Ē in the DRA; wherein the volume of a dielectric material includes a volume of non-gaseous dielectric material having an inner region having a dielectric medium having a first dielectric constant, the volume of non-gaseous dielectric material that is other than the inner region having a second dielectric constant, the first dielectric constant being less than the second dielectric constant; wherein the volume of non-gaseous dielectric material has a cross sectional overall height Hv as observed in an elevation view of the DRA, and a cross sectional overall width Wv in a direction parallel to the defined direction Ē as observed in the plan view of the DRA; and wherein Hv is greater than Wv/2.

A dielectric waveguide filter includes at least four dielectric waveguide resonators arranged along a main coupling path for signal propagation, and main coupling portions each of which is provided between the dielectric waveguide resonators that are adjacent to each other along the main coupling path among the at least four dielectric waveguide resonators. The main coupling portions include an inductive coupling portion and a capacitive coupling portion, and the inductive coupling portion and the capacitive coupling portion are alternately and repeatedly arranged along the main coupling path.

A dielectric waveguide filter includes at least four dielectric waveguide resonators arranged along a main coupling path for signal propagation, and main coupling portions each of which is provided between the dielectric waveguide resonators that are adjacent to each other along the main coupling path among the at least four dielectric waveguide resonators. The main coupling portions include an inductive coupling portion and a capacitive coupling portion, and the inductive coupling portion and the capacitive coupling portion are alternately and repeatedly arranged along the main coupling path.

Resonant cavity filters include a conductive housing having a floor. A dielectric resonator is mounted to extend upwardly from the floor. The dielectric resonator has a cylindrical body with a longitudinal bore that defines an inner sidewall. The longitudinal bore has a variable transverse cross-sectional area. A threaded dielectric fastener is at least partially inserted within the longitudinal bore of the cylindrical body.