HIGH FREQUENCY FILTER

PURPOSE:To obtain a sufficient coupling by providing repeatedly an uneven part of at least one part of opposed coupling parts and lengthening an execution length of the opposed part, in a distributed constant type high frequency filter. CONSTITUTION:In a band-pass filter of two stages formed by a strip line, 8, 9, 10 and 11, and 12, 13 are 14 denote an inputting circuit, an outputting circuit, annular resonance circuits, and opposed coupling parts, respectively. A shape of a part of the opposed coupling parts 12, 13 and 14, and the resonance circuits 10, 11 is formed unevenly like a waveform, and the inptting or outptting circuit, or the resonance circuit opposed to said part is formed unevenly so as to go side by side with this uneven part. As a result, an execution length of a coupling part for coupling an electromagnetic wave is lengthened. As a matter of course, when this structure is used for at least one part or more of the opposed coupling parts 12, 13 and 14, it is effective in its own way. The foregoing shows a case when the strip line is used, but as far as a distributed constant line is concerned, this invention is effective except a line like a closed pipe, and it does not depend at all on a propagation mode, etc.