Abstract: A filter device includes input and output terminals, first and second ground electrodes opposed to each other, and a resonator connected to one of the input and output terminals. The resonator includes a third ground electrode, and first, second, and third resonant portions. The third ground electrode is between and connected to the first and second ground electrodes. The first resonant portion is between the first and third ground electrodes, and connected to the third ground electrode and one of the input and output terminals. The second resonant portion is between the first and third ground electrodes, and connected to the third ground electrode. The third resonant portion is between the second and third ground electrodes, and connected to the third ground electrode.

Abstract: A filter device includes a main body, a ground terminal, ground electrodes, resonators, and a via. The ground electrodes are at different positions in a normal direction of the main body. The resonators are between the ground electrodes and electromagnetically coupled to each other. Each of the resonators includes two capacitor electrodes connected by a via. When the main body is viewed in plan view, each of the capacitor electrodes overlaps a respective one of the ground electrodes. The resonators include first resonators respectively connected to an input terminal and an output terminal, and second resonators between the first resonators. The via is between the second resonators when the main body is viewed in plan view from the normal direction, and is connected to the ground electrodes.

Abstract: A dielectric waveguide filter includes resonators in a dielectric plate. A main coupling portion is between a final stage resonator of a first set and an initial stage resonator of a second set. A trap resonator is between a resonator that is one stage before the final stage resonator of the first set and a resonator that is one stage after the initial stage resonator of the second set, and the trap resonator is coupled to the final stage resonator of the first set and the initial stage resonator of the second set.

Abstract: A filter device includes a dielectric substrate, first and second ground electrodes connected to a ground terminal, and resonators between the ground electrodes and electromagnetically coupled to each other. The ground electrodes are at different positions in a normal direction of the dielectric substrate. Each of the resonators includes a first capacitor electrode partially overlapping with the first ground electrode in plan view of the dielectric substrate, a second capacitor electrode partially overlapping with the second ground electrode in plan view of the dielectric substrate, and a via connecting the capacitor electrodes. The resonators include a first resonator connected to an input terminal, a second resonator connected to an output terminal, and a third resonator between the first and second resonators. Shunt electrodes are connected to the via and the ground terminal in the first and second resonators, respectively.

Abstract: A band pass filter includes a dielectric substrate, conductor plates, a ground via, waveguide resonators, and a trap resonator. The conductor plates are inside the dielectric substrate and opposed to each other. The ground via connects the conductor plates together. The waveguide resonators are coupled in series in a space between the conductor plates along a principal coupling path from an input terminal to an output terminal. Waveguide resonators adjacent along the principal coupling path are subjected to inductive coupling. The trap resonator couples waveguide resonators in two pairs included in the waveguide resonators as jumping over a portion of the principal coupling path, and capacitive couples the waveguide resonators included in each of the pairs.

Abstract: A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

Abstract: A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

Abstract: A dielectric waveguide filter includes a dielectric plate including first and second principal surfaces facing each other and a side surface connecting outer edges of the first and second principal surfaces, a first surface conductor at the first principal surface, a second surface conductor at the second principal surface, a side conductor film inside the dielectric plate and connecting the first and second surface conductors, and an internal conductor extending in a perpendicular direction to the first principal surface and electrically connected to neither the first surface conductor nor the second surface conductor. Dielectric waveguide resonant spaces are surrounded by the first surface conductor, the second surface conductor, and the side conductor film.

Abstract: A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

Abstract: A dielectric waveguide filter includes resonators in a dielectric plate. A main coupling portion is between a final stage resonator of a first set and an initial stage resonator of a second set. A trap resonator is between a resonator that is one stage before the final stage resonator of the first set and a resonator that is one stage after the initial stage resonator of the second set, and the trap resonator is coupled to the final stage resonator of the first set and the initial stage resonator of the second set.

Abstract: 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.

Abstract: A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.