| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the required number of components for matching a SAW filter module. <P>SOLUTION: The SAW filter module 10 obtains matching in impedance matching circuits 11A-11D for the coupling between SAW filters 10A-10D and an RF-IC 20. The real part of the output impedance Zsaw of the SAW filter is made to substantially match with the real part of the input impedance Zic of the RF-IC. The impedance matching circuits change the imaginary part of the output impedance Zm of the SAW filter module, in response to the imaginary part of the input impedance Zic of the RF-IC 20. The impedance matching circuits are constituted of one inductor or capacitor or a plurality of inductors or capacitors by parallel connection, are formed as a printed pattern on the substrate of the module, and define the real part Rsaw and the real part Ric, as substantially 0.8Ric<Rsaw<1.2Ric. <P>COPYRIGHT: (C)2007,JPO&INPIT |
