| 摘要 |
PROBLEM TO BE SOLVED: To provide a balun-incorporated band pass filter which is compact not only in area but also in size of height and has improved characteristics. SOLUTION: The filter circuit has two functions of: a band pass filter to pass a signal in a specific band (2.4 GHz band) and to attenuate the signal in an adjacent band (of which the central frequency is 1.9 GHz); and a balanced/unbalanced conversion circuit. An attenuation circuit section 2 which attenuates a signal component in the frequency band adjacent to a passband is connected to a route where an unbalanced signal is inputted to a first coupling line LC1. Each circuit element is composed of two or three conductive layers stacked on a substrate. COPYRIGHT: (C)2005,JPO&NCIPI
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