Abstract: A dielectric filter having two outside resonators, one middle resonator disposed between the two outside resonators, and a notch pattern is provided. An input pad and an output pad are formed within respective non-coated lateral areas of a lateral surface corresponding to the outside resonators, respectively. The notch pattern is formed within an expanded non-coated lateral area of the lateral surface coupled to one of the non-coated lateral areas of the lateral surface which corresponds to a third position of the lateral surface corresponding to the middle resonator and one of the outside resonators. The notch filter is extended along the lateral surface from the input pad or the output pad toward the middle position corresponding to the middle resonator. The notch filter forms an electrical capacitor between the middle resonator and the input pad or the output pad.

Abstract: A dielectric filter having two outside resonators, one middle resonator disposed between the two outside resonators, and a notch pattern is provided. An input pad and an output pad are formed within respective non-coated lateral areas of a lateral surface corresponding to the outside resonators, respectively. The notch pattern is formed within an expanded non-coated lateral area of the lateral surface coupled to one of the non-coated lateral areas of the lateral surface which corresponds to a third position of the lateral surface corresponding to the middle resonator and one of the outside resonators. The notch filter is extended along the lateral surface from the input pad or the output pad toward the middle position corresponding to the middle resonator. The notch filter forms an electrical capacitor between the middle resonator and the input pad or the output pad.

Abstract: Disclosed is a dielectric filter with improvement in inductive coupling. It comprises a filter body, input-output pad, and an inductive coupling portion. The filter body comprises a block of a dielectric material having top, bottom and grounding surfaces, and having a plurality of through-holes extending from the top to the bottom surfaces defining resonators. The surfaces are substantially covered with a conductive material with the exception that the top surface is uncoated at partial regions around the holes and that one of the grounding surfaces is uncoated at partial regions adjoining the top surface and the bottom surface. The input-output pads are formed on the grounding surface at regions adjoining the top surface, the regions being separated by the uncoated regions adjoining the top surface.