Waveguide filter with coaxial/waveguide mode conversion
AssigneeFujitsu Limited
InventorsKenichi Kudo, Hiroyuki Sogo, Takehiro Shimizu, Masanori Fukuda
Life of this patent
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Abstract
In order to improve filter loss of a waveguide filter having coaxial/waveguide mode conversion parts at its ends, conductor posts bridging a space between two long sides of the waveguide are provided between the parts and the ends. The conductor posts have sufficient thickness and remain close enough to each other and to short ends of the waveguide that a partition plane including axes of the conductor posts can be regarded as an imaginary short plane. The conductor posts are located so that the partition plane is positioned at a distance .lambda./4.times.n (n=1, 3, 5 . . . ) from the coaxial/waveguide mode conversion part.
Claims3
A waveguide filter, comprising:
- a waveguide having two opposite long sides and two opposite short sides which define first and second ends and an interior region;
- a bandpass filter provided in the interior region of the waveguide;
- a coaxial/waveguide mode conversion part provided in the waveguide, for converting a transmission mode between a coaxial mode and a waveguide mode, the bandpass filter being located on a first side of the coaxial/waveguide mode conversion part, toward the first end of the waveguide;
- a plurality of conductor posts which together bridge a space between the two opposite long sides, the conductor posts being located on a second side of the coaxial/waveguide mode conversion part, toward the second end of the waveguide;
- a conductor block inserted into the second end of the waveguide to thereby seal the second end, the distance between a partition plane defined by the conductor posts and the conductor block being substantially .lambda.'/2.times.n (n=1, 2, 3 . . . ) where .lambda.'/ is the wavelength of an electric wave to be eliminated.
Dependencies are inferred from the claim text.