Patent ID: 6085071
Filing Date: 2000-07-04
Classification: H01P

Abstract:
An antenna duplexer comprising a transmission input terminal, a receiving output terminal, an antenna terminal in which a transmission output terminal and a receiving input terminal are used in common, a transmission filter having plural resonance elements set between said transmission input terminal and said transmission output terminal and coupled by a coupling element, a receiving filter having plural resonance elements set between said receiving output terminal and said receiving input terminal and coupled by a coupling element, and plural impedance variable elements individually responsive to control signals, said impedance variable elements including a first plurality thereof and a second plurality thereof, each said impedance variable element of said first plurality thereof being connected to an associated one of said resonance elements of said transmission filter and each said impedance variable element of said second plurality being connected to an associated one of said resonance elements of said receiving filter whereby each resonance element of said transmission filter and each resonance element of said receiving filter is connected to one of said impedance variable elements, each such connected impedance variable element and resonance element being connected in parallel, wherein the frequency transfer characteristic of said transmission filter and the frequency transfer characteristic of said receiving filter are controlled by applying control signals to thereby change the impedance of each of said impedance variable elements individually, and to thereby change the resonance frequency of each of said resonance elements individually.