| 摘要 |
Provided is a front-end circuit which can prevent a signal from leaking into another circuit even when signals are sent and received simultaneously in multiple frequency bands in carrier aggregation. The circuit includes a transmission and reception antenna 91, a double-pole N-throw switch 92 with its common contact connected to the transmission and reception antenna 91, N variable impedance adjustment circuits 17-1 to 17-N each having a terminal on the antenna side, the terminals being respectively connected to N changeover contacts of the switch 92, N duplexers 93-1 to 93-N each having a common terminal, for receiving transmission and reception signals in first to N-th frequency bands, the common terminals being respectively connected to terminals on the RFIC side of the variable impedance adjustment circuits 17-1 to 17-N, a control unit 18 connected to the variable impedance adjustment circuits 17-1 to 17-N and the switch 92 by control lines, for controlling switching operations of the variable impedance adjustment circuits 17-1 to 17-N and the switch 92, and an RFIC 16 for sending a control signal to the control unit 18. |
