Patent ID: 7170373

Claim:
A dielectric waveguide filter, comprising: an upper conductive layer and a lower conductive layer on the surfaces of a dielectric substrate; and conductors for connecting said upper conductive layer and said lower conductive layer to form a number, n, of filter stages comprising resonators and dielectric windows; wherein the number, n, of filter stages is 3 or more, and first to n th resonators are successively coupled by electromagnetic fields and are also adjacent to respective resonators such that an i th resonator is coupled by an electromagnetic field to a j th resonator by a window coupling similar to said coupling between through said dielectric windows said resonators which are successively coupled, where 1≦i<j≦n and j≠i+1, wherein said resonators are formed by via-hole rows that connect said upper conductive layer and said lower conductive layer, and the spacing of via-holes that form the via-hole rows is less than or equal to ½ the guide wavelength of the resonance frequency.