Patent ID: 6373352
Filing Date: 2002-04-16
Classification: H01P

Abstract:
A duplexer having stepped impedance resonators which are formed in a dielectric block coated with a conductive film, wherein the duplexer includes a transmitting filter, a receiving filter and an impedance matching circuit, the duplexer comprising:a) a plurality of open ended resonators arranged in a front side of the dielectric block, the open ended resonators includes: a-1) a plurality of first apertures, each of which passes through the dielectric block from an upper surface thereof to a bottom surface thereof, wherein inner surfaces of the first apertures are coated with the conductive film; and a-2) a plurality of uncoated gaps round the first apertures on the upper surface of the dielectric block, b) a plurality of shorted resonators arranged in a rear side of the dielectric block, the shorted resonators includes: b-1) a plurality of second apertures, each of which passes through the dielectric block from the upper surface thereof to the bottom surface thereof, wherein each shorted resonators corresponds to the open ended resonators and wherein inner surfaces of the second apertures are coated with the conductive film, c) a plurality of recesses formed at the bottom of the dielectric block, extending from the first apertures of the open ended resonators to the second apertures of the shorted resonators, wherein the recesses are coated with the conductive film, d) a plurality of first grooves for controlling receiving coupling at the receiving filter, each of which is formed in the rear side of the dielectric block at the receiving filter, wherein the first grooves are formed from the upper surface of the dielectric block to the bottom surface of the dielectric block; and e) a plurality of second grooves for controlling transmitting coupling at the transmitting filter, each of which is formed in the front side of the dielectric block at the transmitting filter, wherein the second grooves are formed from the upper surface of the dielectric block to the bottom surface of the dielectric block.