| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit board where costs are reduced and wasteful spaces are not generated, while suppressing the deterioration of filter characteristic, and to provide a cellular phone which can be miniaturized. SOLUTION: In a circuit block 40 where first and second inductors 11 and 12, having the same winding direction are connected adjacently to both of the end of a filter 30 for impedance matching, the first inductor 11 has a second terminal 22 connected to a wire 25a extending from a first port 41 to the input terminal of the filter 30, and has a first terminal 21 connected to a ground terminal 27. A second inductor 12 has the first terminal 21 connected to a wire 25b extending from the output terminal of the filter 30 to the second port 42 of the circuit block, and has the second terminal 22 connected to the ground terminal 27. With this constitution, the first inductor 11 and the second inductor 12 are capacity-coupled by a parasitic capacity 29 and mutual inductance M becomes positive to generate resonance, thereby suppressing the deterioration of the filter characteristics. COPYRIGHT: (C)2006,JPO&NCIPI
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