| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the loss of insertion of an antenna switch by connecting a 1st external terminal of receiving amplifier input, a 2nd external terminal of transmitting amplifier output, a switch and one of both ends of each of 1st and 2nd reactance elements to the 3rd and 4th external terminals of an integrated circuit and connecting the other end of each of 1st and 2nd reactance elements to an antenna respectively. SOLUTION: In a reception mode, the 1st and 2nd switches 6 and 7 are off and turned on respectively. A 4th external terminal 11 is short-circuited via the ground by the switch 7. The impedance is increased in the direction of the terminal 11 against an antenna terminal 14 which is set to a 1st inductor element 12 and a matching circuit 15. In a transmission mode, the switches 6 and 7 are turned on and off respectively. A 3rd external terminal 10 is short- circuited via the ground by the switch 6. The impedance increases in the direction of the terminal 10. The terminal 14 is set to a 2nd inductor element 13 and the circuit 15. Then both elements 12 and 13 are located outside an integrated circuit.</p> |
