| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that many switch elements are required, and attenuation in a signal at each path is increased when a configuration formed by roughly dividing a frequency region using a band branching filter and then by switching the path of each frequency by using switching elements is employed. <P>SOLUTION: A transmission system-path switching circuit 17 having the switch elements 20, 23 at its antenna terminal 11 side is arranged. A reception system-path switching circuit 18 having the band branching filter 24 located at a remote side from the antenna terminal 11 is arranged. Isolation between the transmission path and the reception path is ensured by using a 1/4-wavelength line 19. In addition, the use of the band branching filter 24 as well as the switch elements 20, 23, 25, 26 for separating each path materializes low loss at each path in the multi-path. <P>COPYRIGHT: (C)2004,JPO |
