| 摘要 |
PROBLEM TO BE SOLVED: To make the changeover circuit small, to reduce power consumption at reception and to transmit a high power signal at transmission by employing a FET switch for diversity reception changeover and a PIN diode switch for transmission/reception changeover respectively. SOLUTION: When a low level is given to a control terminal 105 and a high level is given to a control terminal 106, an antenna connection terminal 101 and a reception terminal 104 are conductive and an antenna connection terminal 102 and the reception terminal 104 are nonconductive. When a parallel FET 115 is conductive, a connecting point between serial FETs 113, 115 has low impedance. High impedance on the terminal 104 is obtained by connecting a λ/4 line 112 to this point via a DC block capacitor 111. In this case, when a high level is given to a control terminal 107, a serial PIN diode 108 is conductive so as to make the terminal 101 and a transmission terminal 103 conductive and the terminal 101 and the reception terminal 104 are nonconductive. |
