A multi-mode cavity filter includes: a metal cavity formed into a hollow shape; and a plurality of resonators supported in suspension within the metal cavity and not contacting with an inner wall of the metal cavity. The plurality of resonators includes: a first resonator configured to generate a first resonant frequency; and a second resonator electrically connected to the first resonator and configured to generate a second resonant frequency. The second resonator includes a plurality of resonance plates. A first number of the second resonant frequency is associated with a second number of the plurality of resonance plates.

A multi-mode cavity filter includes: a metal cavity formed into a hollow shape; and a plurality of resonators supported in suspension within the metal cavity and not contacting with an inner wall of the metal cavity. The plurality of resonators includes: a first resonator configured to generate a first resonant frequency; and a second resonator electrically connected to the first resonator and configured to generate a second resonant frequency. The second resonator includes a plurality of resonance plates. A first number of the second resonant frequency is associated with a second number of the plurality of resonance plates.

Embodiments of this application disclose a dielectric filter and a communication device. In one example, the dielectric filter includes: a first dielectric block and a second dielectric block that are stacked up, where a first surface of the first dielectric block is opposite to a second surface of the second dielectric block; a first blind hole, a first through hole, and two or more resonance through holes whose openings are located on the first surface of the first dielectric block, and a second through hole whose opening is located on the second surface of the second dielectric block. A metal layer on the first surface of the first dielectric block is connected to a metal layer on the second surface of the second dielectric block.

When a plurality of RF signals having different frequer bands are output at the same time by carrier aggregation, a switch element allows parallel connection between two capacitance elements such that a low pass filter has a first cut-off frequency that is lower than the frequency of an intermodulation distortion signal generated by the carrier aggregation. When an RF signal of a frequency band is output, the switch element releases parallel connection between the two capacitance elements such that the low pass filter has a second cut-off frequency that is higher than the first cut-off frequency.

When a plurality of RF signals having different frequer bands are output at the same time by carrier aggregation, a switch element allows parallel connection between two capacitance elements such that a low pass filter has a first cut-off frequency that is lower than the frequency of an intermodulation distortion signal generated by the carrier aggregation. When an RF signal of a frequency band is output, the switch element releases parallel connection between the two capacitance elements such that the low pass filter has a second cut-off frequency that is higher than the first cut-off frequency.

In-line filters may include a tubular metallic housing defining a single inner cavity that extends along a longitudinal axis and a plurality of resonators that are spaced apart along the longitudinal axis within the single inner cavity, each resonator having a stalk. The stalks of first and second of the resonators that are adjacent each other are rotated to have different angular orientations.

In-line filters may include a tubular metallic housing defining a single inner cavity that extends along a longitudinal axis and a plurality of resonators that are spaced apart along the longitudinal axis within the single inner cavity, each resonator having a stalk. The stalks of first and second of the resonators that are adjacent each other are rotated to have different angular orientations.

An apparatus includes a filter. The filter includes a metal structure forming a cavity and includes a ceramic block, which is suspended in the cavity. The ceramic block has two removed portions, the removed portions removed from two opposing sides of the ceramic block. The ceramic block further has one or more slots that that span a region of ceramic between the two removed portions and connects chambers formed by the two regions with chambers formed by the one or more slots, wherein a combined structure of the ceramic block, cavity, and metal structure supports multiple fundamental TM modes and one fundamental TE mode. The filter comprises multiple coupling structures to couple radio frequency signals into and out of the filter. The apparatus may include multi-cavity filters including one and typically multiple ones of the filters.

An apparatus includes a filter. The filter includes a metal structure forming a cavity and includes a ceramic block, which is suspended in the cavity. The ceramic block has two removed portions, the removed portions removed from two opposing sides of the ceramic block. The ceramic block further has one or more slots that that span a region of ceramic between the two removed portions and connects chambers formed by the two regions with chambers formed by the one or more slots, wherein a combined structure of the ceramic block, cavity, and metal structure supports multiple fundamental TM modes and one fundamental TE mode. The filter comprises multiple coupling structures to couple radio frequency signals into and out of the filter. The apparatus may include multi-cavity filters including one and typically multiple ones of the filters.

An RF filter includes: an electrical conductor defining an outer sphere; a dielectric material defining an inner sphere disposed within the conductor outer sphere; and at least a first electrical probe and a second electrical probe. Each probe extends through the conductor and is electrically insulated from it. A spherical shape of one or both of the inner and outer spheres is interrupted by: a) a first localized discontinuity in said spherical shape disposed along a first axis passing through a geometric center of the one or both of the inner and outer spheres; and b) a second localized discontinuity in said sphere form disposed along a second axis passing through the geometric center, the second axis perpendicular to the first axis. There can be more than these two discontinuities, implemented as chamfers, tuning screws, and the like. Series and parallel coupling of the spheres is detailed.