| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized and low-price broadband band-pass filter. SOLUTION: The band-pass filter is provided with a first line 1 and a second line 2, disposed oppositely to each other through a dielectric, and constituting a coupled line, and ground surface bodies 3a, 3b disposed in the vicinity of the coupled line. Thickness-direction side surfaces T of the first line 1 and the second line 2 and thickness-direction side surfaces T of the ground surface bodies are opposed to each other, thereby reducing a capacity formed between the coupled line and the ground surface bodies, which holds an even mode impedance Ze>>an odd mode impedance Zo. This means passing-through (S11=0) except at the resonance frequency (cutting-off in between 0 and the resonance frequency), which achieves the broadband band-pass filter passing 0-the resonance frequency therethrough. COPYRIGHT: (C)2009,JPO&INPIT
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