WAVEGUIDE CONVERSION DEVICE, WAVEGUIDE ROTARY JOINT, AND ANTENNA DEVICE

摘要

It is possible to improve the transmission efficiency of a necessary transmission mode by providing an unnecessary wave suppression groove for suppressing excitation of an unnecessary transmission mode in a mode conversion portion between a rectangular waveguide and a circular waveguide. The rectangular waveguide (2) is vertically connected to the circular waveguide (4) and at the mode conversion portion of them, there is provided the unnecessary wave suppression groove (5) extending along the walls (2B, 2C, 2D) of the rectangular waveguide (2) and the wall (4A) of the circular waveguide (4). Thus, the unnecessary wave suppression groove (5) can suppress excitation of a TE11 mode unnecessary in the circular waveguide (4) by an electromagnetic wave of a TE10 mode propagating in the rectangular waveguide (2), thereby reducing the conversion loss to the TE11 mode. Moreover, it is possible to effectively excite the electromagnetic wave of a TM01 mode in the circular waveguide (4) and stably transmit a signal between the waveguides (2, 4).