| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a small-sized RF stage module that reduces number of the components, having superior attenuation characteristics of harmonics and low power consumption. SOLUTION: The RF stage module is provided with a switch circuit that is placed among a transmission circuit, a reception circuit and an antenna and controls the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna, and a 1st balance-unbalanced circuit placed in between the switch circuit and the transmission circuit. The 1st balance-unbalanced circuit is provided with a 1st transmission line, a 2nd transmission line and a 3rd transmission line, which electromagnetically couple to the 1st transmission line. A balun transformer is provided, where the one terminal of the 1st transmission line is connected to an unbalance terminal of the balun transformer, the other terminal of which is used for a grounded or open terminal, one terminal of the 2nd transmission line is connected to ground, the other terminal of which is connected to a 1st balanced terminal of the balun transformer, one terminal of the 3rd transmission line is connected to ground, the other terminal of which is connected to a 2nd balance terminal of the balun transformer, and one-sided terminals of the 2nd and 3rd transmission lines, connected to the balun transformer configuring the 1st balance-unbalanced circuit are connected together and to ground via a capacitor.</p> |
