| 摘要 |
PROBLEM TO BE SOLVED: To miniature a band-pass filter applicable to a super-broadband radio system enabling high speed transmission. SOLUTION: The band-pass filter, used for a balancing circuit, comprises a dielectric 9, a pair of first lines 1, 1 arranged on a first surface of the dielectric symmetrically with each other with respect to a symmetrical plane C crossing with the first surface, and a pair of second lines 2, 2 arranged on a second surface of the dielectric symmetrically with each other with respect to the symmetrical plane. Line widths of the first lines and the second lines at their input-output ends and their opening ends 3-6 wider than at their intermediate portions are increased, thereby decreasing a high-pass side cutoff frequency. This makes shorter the line length of the band-pass filter according to the present invention, thereby further miniaturizing the band-pass filter, comparing the band-pass filter according to the present invention and the conventional band-pass filter with each other, both of which having the same cutoff frequency. COPYRIGHT: (C)2009,JPO&INPIT
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