| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a problem that the reflection wave of a transmission signal returns back to the transmission circuit side, or a problem that the reflection wave of a transmission signal leaks to the reception circuit side, even if antenna mismatch occurs due to close approach of an object or a human body to an antenna.SOLUTION: A front-end circuit includes a transmission signal filter 11 passing a transmission signal, a reception signal filter 12 passing a reception signal, and a circulator (antenna duplexer) 13, and a transmission output variable circuit 20 is connected between the transmission signal terminal of the circulator 13, and transmission signal filter 11. The transmission output variable circuit 20 includes a first high frequency switch 21, a second high frequency switch 22, and a buffer circuit 23, and attenuation is switched by switching the first high frequency switch 21 and second high frequency switch 22. |
