Front-end module for triple-band mobile phones

摘要

PROBLEM TO BE SOLVED: To provide a front-end module for portable telephone which can decrease circuit elements and is reducible in size when one portable telephone is used for three communication systems. SOLUTION: This module has notch circuits 12 and 13A which are connected to an antenna 5. Further, the module has an antenna switch 7 (24) which switched and connects a transmitting circuit 2 (23) and a receiving circuit 1 (3 and 17) to the corresponding notch circuit. Furthermore, the module has filters 10 and 11A which remove higher harmonics. One notch circuit 13A is used in common for two communication systems. The antenna switch 24 connected to the notch circuit 13A used in common is used in common for the transmitting circuit 23 used for the two communication systems.