Dielectric filter with recessed end surface

摘要

A dielectric filter, having a dielectric block with an outer surface including first and second end surfaces and a side surface extending between the first and second end surfaces; an external conductor disposed on the outer surface of the dielectric block, the external conductor substantially completely covering the outer surface; at least one hole extending through the dielectric body between the first and second end surfaces, the at least one hole having an inner surface; the at least one hole having a respective pair of internal conductors disposed on its corresponding inner surface and conductively connected to the external conductor respectively at the first and second end surfaces, a respective non-conductive portion at the corresponding inner surface being spaced from both of the end surfaces and thereby separating the corresponding pair of internal conductors and defining a respective capacitance between the corresponding pair of internal conductors; a predetermined portion of one of the first and second end surfaces of the dielectric block having a shape such that a first portion of the external conductor at the predetermined portion is closer to at least one of the internal conductors of the at least one hole, as compared with a second portion of the external conductor at a portion of the dielectric block other than the predetermined portion.