| 摘要 |
<p>A microwave filter is disclosed in which open-ended lines (14, 15, 16) are connected at three or four points of a main line (13) having input and output terminals (11, 12) the open-ended lines (14, 15, 16) having a length about one fourth the wavelength of an image signal frequency, to produce a band-stop filter characteristic at an image frequency; all or parts of the open-ended lines (14, 15, 16) constitute open-ended parallel-coupled lines arranged in parallel to the main line (13), and the intervals of connection of the open-ended lines (14, 15, 16) with the main line (13) are properly selected. The insertion loss of the filter within the pass band of a radio frequency signal is reduced and the filter attenuation within a stop band of an image signal is increased, thus providing a compact band-stop filter which has a steep rise characteristic.</p> |
