| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a balun applicable to a push pull power amplifier, enabling injection or extraction of a second-order harmonic wave, or application of a DC bias, to the push pull power amplifier through the balun. <P>SOLUTION: A balun having a length of 1/4 wavelength to a fundamental wave f<SB POS="POST">0</SB>and formed using two coupling transmission lines 11 and 12 with equivalent performance includes a frequency selective impedance circuit 23 for switching a short circuit and an open circuit by a frequency so as to be inputted to inject or extract a second-order harmonic wave, or apply a DC bias. Accordingly, this enables injection or extraction of the second-order harmonic wave and application of the DC bias, to a push pull power amplifier through the balun 103. <P>COPYRIGHT: (C)2013,JPO&INPIT |
