DUPLEXER CIRCUIT, ESPECIALLY RELATED TO SELECTIVELY DRIVING PLURAL NARROWBAND FILTERS TO IMPROVE ATTENUATION FEATURES

摘要

PURPOSE: A duplexer circuit is provided to dispose plural narrowband filters in a transmission terminal and a receiving terminal, and to use a PIN diode and an SPDT switch element whose switching speed is very fast, thereby improving signal attenuations while expanding a bandwidth. CONSTITUTION: An antenna transceives two frequency band signals. A receiving terminal(Rx) receives the signals. A transmission terminal(Tx) transmits signals generated from a system through the antenna. The first and second transmission filters(201a,201b) have narrow bandwidths in the transmission terminal(Tx). The first and second receiving filters(202a,202b) having narrow bandwidths are disposed in the receiving terminal(Rx). The first and second transmission phase shifts(203a,203b) are disposed on both sides of the two transmission filters(201a,201b). The third transmission phase shift(203c) controls phases of signals filtered in the two transmission filters(201a,201b). The first and second receiving phase shifts(205a,205b) are disposed on both sides of the two receiving filters(202a,202b). The third receiving phase shift(205c) controls phases of signals filtered in the two receiving filters(202a,202b).