Dielectric filter

A dielectric filter, comprising:

• a dielectric block substantially in the form of a rectangular parallelepiped having two main surfaces, top and bottom surfaces, and two side surfaces, said dielectric block being formed with a plurality of throughholes extending from said top surface to said bottom surface in a direction parallel with said two main surfaces, respective inner conductors being formed on inner surfaces of said throughholes, an outer conductor being formed on an outer surface of said dielectric block, said outer conductor being formed on at least one of said top and bottom surfaces, said inner conductors and said outer conductor forming a plurality of coaxial resonators in said dielectric block, and said ends of said resonators at said surface where no outer conductor is formed being open ends of the resonators;
• a printed circuit board disposed adjacent and substantially parallel with said open ends of said dielectric resonators with a predetermined gap defined between said printed circuit board and said block;
• a metallic case in which said dielectric block and said printed circuit board are accommodated, said metallic case being connected to said outer conductor and having a bottom plate;
• and
• a projecting portion which is formed on an inner surface of said metallic case and supports said printed circuit board to maintain a predetermined gap between said printed circuit board and said bottom plate of said metallic case.