PURPOSE: To prevent the leak of radio waves and to eliminate the instability of electric characteristics due to the variance of fitting precision by providing a 1/4-wavelength folded choke in a thick part of the end part, which is inserted into an outside waveguide, of an inside waveguide.
CONSTITUTION: A 1/4-wavelength folded choke 4 is provided in a thick part of the end part, which is inserted into an outside waveguide 1, of an inside waveguide 2. Lengths A-B and B-C-D of this 1/4-wavelength folded choke 4 correspond to a 1/4 of the wavelength of a specific mode wave or a space propagation wave in the waveguide to attain electric short-circuit. One of long sides facing each other and one side of short sides facing each other of the inside waveguide are cut in positions, which are a 1/4 of the transmission wavelength in the waveguide distant from the front end of the waveguide, for the purpose of attaining matching in the end part of the inside waveguide, thus constituting an equivalent 1/4-wavelength transformer. Consequently, the instability of electric characteristics due to the variance of fitting precision is improved.
KOMAI TOMOO
OKUYAMA AKIRA
SAITOU KATSUO
MITSUBISHI ELECTRIC CORP