A coaxial filter having a frame construction comprises at least one filter frame, which consists of an electrically conductive medium and comprises a receiving space. A cover arrangement closes the receiving space on all sides. At least one first resonator internal conductor is arranged in the receiving space. The at least one first resonator internal conductor is galvanically connected to a face of the at least one electrically conductive filter frame, and extends therefrom in the direction of another, in particular opposing face of the electrically conductive filter frame, and ends at a distance from the opposing face of the electrically conductive filter frame and/or is galvanically separated from the opposing face of the electrically conductive filter frame.

A filter includes series resonators on a signal path, each of the series resonator including an IDT electrode that includes first electrode fingers each including a variant portion, second electrode fingers each including no variant portion, or both the first electrode fingers and the second electrode fingers, in the IDT electrode of one or more series resonators of the series resonators, a direction connecting other-side end portions of electrode fingers crosses an acoustic wave propagation direction, the IDT electrode includes the first electrode fingers, a first portion of an IDT electrode of another series resonator centrally located in the acoustic wave propagation direction, includes only the first electrode fingers, and a second portion and a third portion on two sides of the first portion each include only the second electrode fingers.

The present disclosure provides a cavity filter assembly installed with an RF filter having an empty area formed between the RF filter and a cavity filter body serving as a ground to reduce the parasitic capacitance by forming the cavity filter body with a first pocket portion configured to install the RF filter and a second pocket portion within the first pocket portion in a position to overlap a transmission line, thereby reducing the insertion loss of the RF filter, which when serving as a low-pass filter, can position the harmonics in the stopband further away from the cutoff frequency and thus effect improved frequency characteristics of the low-pass filter through improvements of, for example, the frequency characteristics in the stopband.

A cavity filter includes a cavity, a cover plate, a tuning component, and a resonant column. The cover plate is connected to the cavity, and the cover plate is configured to cover the cavity to form a resonant cavity. A through hole is provided on the cover plate, and the tuning component passes through the through hole and is fastened on the cover plate. The tuning part includes a high-conductivity part and a non-conductivity part, the high-conductivity part is located in the cavity, and the resonant column is in the cavity.

A cavity filter includes a cavity, a cover plate, a tuning component, and a resonant column. The cover plate is connected to the cavity, and the cover plate is configured to cover the cavity to form a resonant cavity. A through hole is provided on the cover plate, and the tuning component passes through the through hole and is fastened on the cover plate. The tuning part includes a high-conductivity part and a non-conductivity part, the high-conductivity part is located in the cavity, and the resonant column is in the cavity.

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 are embodiments of ceramic radiofrequency filters advantageous as RF components. The ceramic filters can include a ceramic stepped impedance resonator, wherein the inner diameter of the ceramic stepped impedance resonator can vary from one end to another end. The inner diameter can be, for example, tapered, sectioned, or stair-stepped in order to provide different impedances in the ceramic resonator.

A cross-coupled filter includes a minimum resonant structure including four resonators. In the minimum resonant structure, two resonators in the same row form a group, and two resonators in the same row are capacitively mainly coupled or inductively mainly coupled; two resonators in the same column are electrically and magnetically hybrid coupled; and the coupling polarities of the two groups of resonators in the two rows of resonant units are opposite to each other and form at least a cross-coupling. The invention realizes miniaturization and light weight in structural characteristics, and realizes low loss and good harmonic characteristics in electrical performance.

A cross-coupled filter includes a minimum resonant structure including four resonators. In the minimum resonant structure, two resonators in the same row form a group, and two resonators in the same row are capacitively mainly coupled or inductively mainly coupled; two resonators in the same column are electrically and magnetically hybrid coupled; and the coupling polarities of the two groups of resonators in the two rows of resonant units are opposite to each other and form at least a cross-coupling. The invention realizes miniaturization and light weight in structural characteristics, and realizes low loss and good harmonic characteristics in electrical performance.

Adaptive RF filters based on modulated resonators are provided. The filter architecture is based on time-interleaved commutation of passive RF resonators. The architecture can behave as a two-port filter network, with a fully tunable instantaneous filter bandwidth. The filters are applicable as miniaturized, environment-aware RF signal processing components and can be used in mobile communications.