| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in a conventional technique that noises in a rejection band cannot be sufficiently eliminated because there is a limitation in steepening attenuation when a pass band is close to the rejection band. SOLUTION: The band rejection filter is formed to laminate a first coil, a first capacitor connected to the first coil in parallel, a second coil and a second capacitor connected in series between an input side of the first coil and a ground thereof, and a third coil and a third capacitor connected in series between an output side of the first coil and the ground thereof. The first coil, the second coil and the third coil are formed so that the inductance value of the second coil is larger than the inductance value of each of the first coil and the third coil. The coils are arranged in the laminate so that a magnetic coupling coefficient between the second coil and the third coil may be smaller than absolute values of a magnetic coupling coefficient between the first coil and the second coil, a magnetic coupling coefficient between the first coil and the third coil in a state where the magnetic coupling coefficient between the first coil and the second coil is positive, and the coupling coefficient between the first coil and the third coil is negative. COPYRIGHT: (C)2006,JPO&NCIPI
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