| 摘要 |
<p>Provided is a surface acoustic wave filter device provided with first and second surface acoustic wave filters with different fractional bandwidths, capable of facilitating excellent impedance matching both in the first and second surface acoustic wave filters, thereby making it possible to facilitate the reduction of an insertion loss into a passband and improvement in a VSWR characteristic. A surface acoustic wave filter device (1) is provided with first and second surface acoustic wave filters (11, 12) having a balanced-unbalanced conversion function. A pair of balanced terminals of the first and second surface acoustic wave filters (11, 12) are connected to first and second balanced terminals (3, 4) and an impedance matching inductance (10) is connected between the first and second balanced terminals (3, 4). The electromechanical coupling coefficient of the first surface acoustic wave filter (11) with a relatively wide fractional bandwidth is larger than the electromechanical coupling coefficient of the second surface acoustic wave filter (12).</p> |
