Dielectric filter with non-conductive edge

A dielectric filter comprising:

• a dielectric block having oppositely disposed rectangular end surfaces and an outer peripheral surface therebetween;
• a plurality of resonators provided in the dielectric block in parallel with respect to each other, each of the resonators including a through hole provided to be extended between the oppositely disposed end surfaces of the dielectric block and an internal conductor provided on an inner peripheral surface of the respective through hole;
• an external conductor provided on a substantial portion of the outer peripheral surface of the dielectric block, one of the end surfaces being a rectangular short-circuit end surface provided with a short-circuiting conductor for connecting the respective internal conductors of the resonators with the external conductor on the outer peripheral surface, and the other end surface being a rectangular open-circuit end surface;
• a non-conductive region of short-circuiting conductor provided on the short-circuit end surface for intensifying a magnetic coupling of the respective resonators, said non-conductive region (a) extending longitudinal along a longer edge of the rectangular short-circuit end surface in parallel with a direction connecting the respective resonators, (b) beginning laterally at an intersection with an adjacent peripheral surface and (c) having a longitudinal width equal to or larger than a distance between the through holes of the outermost resonators.