| 摘要 |
PROBLEM TO BE SOLVED: To provide a low pass filter that both transmission and reflection are reduced in an attenuating region and the power can be absorbed inside. SOLUTION: Inside a substrate 2 made of dielectric materials whose dielectric tangents in frequencies 1 MHz are >=0.001, two ground layers 3 and 5 and a line layer 4 interposed between the ground layers are included. In this case, ground electrodes 3a and 5a are formed over almost the whole face of the ground layers 3 and 5, and meandering line 4a is formed on the line layer 4 so that strip lines in a triplate structure can be constituted as a whole. Then, the both ends of the line 4a are connected with an input terminal 6 and an output terminal 7. In this case, the dielectric tangents of the dielectric materials are set larger than those of dielectric materials for general strip lines. Therefore, as the frequencies of a signal become higher, attenuating amounts due to the dielectric loss are increased so that a low pass filter that reflection in the attenuating area is reduced can be realized.
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