FIELD OF THE INVENTION

The invention relates generally to dielectric waveguide filters and, more specifically, to a dielectric waveguide filter with a trap resonator.

BACKGROUND OF THE INVENTION

This invention is related to a dielectric waveguide filter of the type disclosed in U.S. Pat. No. 5,926,079 to Heine et al. in which a plurality of resonators are spaced longitudinally along the length of a monoblock and in which a plurality of slots/notches are spaced longitudinally along the length of the monoblock and define a plurality of bridges between the plurality of resonators which provide a direct inductive/capacitive coupling between the plurality of resonators.

The attenuation characteristics of a waveguide filter of the type disclosed in U.S. Pat. No. 5,926,079 to Heine et al. can be increased through the incorporation of zeros in the form of additional resonators located at one or both ends of the waveguide filter. A disadvantage associated with the incorporation of additional resonators, however, is that it also increases the length of the filter which, in some applications, may not be desirable or possible due to, for example, space limitations on a customer's motherboard.

The attenuation characteristics of a filter can also be increased by both direct and cross-coupling the resonators as disclosed in, for example, U.S. Pat. No. 7,714,680 to Vangala et al. which discloses a monoblock filter with both inductive direct coupling and quadruplet cross-coupling of resonators created in part by respective metallization patterns which are defined on the top surface of the filter and extend between selected ones of the resonator through-holes to provide the disclosed direct and cross-coupling of the resonators.

Direct and cross-coupling of the type disclosed in U.S. Pat. No. 7,714,680 to Vangala et al. and comprised of top surface of metallization patterns is not applicable in waveguide filters of the type disclosed in U.S. Pat. No. 5,926,079 to Heine et al. which includes only slots and no top surface metallization patterns.

The present invention is thus directed to a dielectric waveguide filter with a trap resonator.

SUMMARY OF THE INVENTION

The present invention is generally directed to a dielectric waveguide filter comprising a first solid block of dielectric material covered with a layer of conductive material and defining a plurality of resonators, a second solid block of dielectric material coupled to the first solid block of dielectric material, the second block of dielectric material covered with a layer of conductive material and defining a plurality of resonators including first and second adjacent resonators separated by an RF signal isolator for preventing the transmission of an RF signal between the first and second resonators, and an RF signal coupling window providing a coupling between a first one of the plurality of resonators of the first block of dielectric material and the first resonator of the second block of dielectric material whereby the first resonator of the second block of dielectric material defines a trap resonator.

In one embodiment, the first RF signal input/output is defined on an end one of the plurality of resonators of the first solid block of dielectric material and the first and second adjacent resonators of the second solid block of dielectric material comprised end ones of the resonators of the second solid block of dielectric material.

In one embodiment, the RF signal isolator comprises a plurality of spaced apart through-holes positioned between the first and second adjacent resonators.

In one embodiment, the RF signal coupling window is defined by a region on the first and second solid blocks of dielectric material that is devoid of conductive material.

In one embodiment, a first RF signal input/output through-hole is defined in the first one of the plurality of resonators of the first block of dielectric material.

In one embodiment, a third solid block of dielectric material is covered with a layer of conductive material and defines the trap resonator, the third solid block of dielectric material being coupled to the first and second solid blocks of dielectric material in a relationship abutting an end region of the first solid block of dielectric material and adjacent an end of the second block of dielectric material.

In one embodiment, an elongate slot is defined between the second and third solid blocks of dielectric material, the elongate slot defining the RF signal isolator for preventing the transmission of the RF signal between the second and third solid blocks of dielectric material.

In one embodiment, the RF signal coupling window is defined by a capacitive coupling isolated pad of conductive material on the first and third solid blocks of dielectric material.

The present invention is also directed to a dielectric waveguide filter comprising a first solid block of dielectric material covered with a layer of conductive material and defining a plurality of resonators, a first RF signal input/output through-hole defined in a first end resonator of the plurality of resonators of the first block of dielectric material, a second solid block of dielectric material coupled to the first solid block of dielectric material, the second block of dielectric material covered with a layer of conductive material and defining a plurality of resonators including first and second adjacent end resonators separated by an RF signal isolator for preventing the transmission of an RF signal between the first and second end resonators, and an RF signal coupling window for providing a coupling between the first end resonator of the plurality of resonators of the first block of dielectric material and the first end resonator of the second block of dielectric material whereby the first end resonator of the second block of dielectric material defines a trap resonator.

In one embodiment, the RF signal isolator comprises a plurality of spaced apart through-holes positioned between the first and second adjacent resonators.

In one embodiment, the RF signal coupling window is defined by a region on the first and second solid blocks of dielectric material that is devoid of conductive material.

In one embodiment, a first RF signal input/output is defined on the first one of the plurality of resonators of the first block of dielectric material.

In one embodiment, a third solid block of dielectric material is covered with a layer of conductive material and defines the trap resonator, the third solid block of dielectric material being coupled to the first and second solid blocks of dielectric material in a relationship abutting the end resonator of the first solid block of dielectric material and adjacent an end of the second block of dielectric material.

In one embodiment, an elongate slot is defined between the second and third solid blocks of dielectric material, the elongate slot defining the RF signal isolator for preventing the transmission of the RF signal between the second and third solid blocks of dielectric material.

In one embodiment, the RF signal coupling window is defined by a capacitive coupling isolated pad of conductive material on the first and third solid blocks of dielectric material.

The present invention is further directed to a dielectric waveguide filter comprising a first solid block of dielectric material covered with a layer of conductive material and defining a plurality of resonators, a second solid block of dielectric material coupled to the first solid block of dielectric material, the second block of dielectric material covered with a layer of conductive material and defining a plurality of resonators including a first end resonator, a third solid block of dielectric material coupled to the first solid block of dielectric material and positioned adjacent an end of the second solid block of dielectric material and defining a resonator, a slot between the second and third solid blocks of dielectric material and defining an RF signal isolator for preventing the transmission of an RF signal between the first end resonator of the second solid block of dielectric material and the resonator of the third solid block of dielectric material, and an RF signal coupling window providing a coupling between a first one of the plurality of resonators of the first block of dielectric material and the resonator of the third block of dielectric material whereby the resonator of the third block of dielectric material defines a trap resonator.

Other advantages and features of the present invention will be more readily apparent from the following detailed description of the preferred embodiment of the invention, the accompanying drawings, and the appended claims.

