Patent ID: 6922120

Claim:
A dielectric filter having a designated resonant frequency, said filter comprising: a dielectric block having a first surface, a second surface being opposite to the first surface, and side surfaces disposed between the first and second surfaces, the side surfaces and the second surface being deposited with a conductive material; a plurality of resonators including resonant holes passing through the first and second surfaces of the dielectric block, being arranged in parallel, and having interior surfaces being deposited with a conductor; input and output terminals formed on the side surfaces of the dielectric block while being separated from the conductive material deposited on the side surfaces; conductive patterns formed on at least a part of the area of the first surface so that the resonators have a desired resonant frequency by changing capacitances of the resonators and/or between the resonators; and a protection layer formed on the first surface provided with the conductive patterns by depositing a thermosetting resin thereon, wherein said protection layer covers the whole surface of the conductive patterns.