WAVEGUIDE CONVERSION DEVICE, WAVEGUIDE ROTARY JOINT, AND ANTENNA DEVICE

摘要

To improve the transmission efficiency of a necessary transmission mode by providing an unnecessary-wave suppression groove that prevents an unnecessary transmission mode from being excited at a mode conversion part between a rectangular waveguide and a circular waveguide. A rectangular waveguide 2 is connected to a circular waveguide 4 at right angles, and an unnecessary-wave suppression groove 5 that extends along tube walls 2B, 2C, and 2D of the rectangular waveguide 2 and a tube wall 4A of the circular waveguide 4 is provided at a mode conversion part between the rectangular waveguide 2 and the circular waveguide 4. Thus, the unnecessary-wave suppression groove 5 can prevent an unnecessary TE 11 mode from being excited in the circular waveguide 4 due to electromagnetic waves of the TE 10 mode that transmit through the rectangular waveguide 2, thereby reducing conversion loss due to the TE 11 mode. Accordingly, electromagnetic waves of the TM 01 mode can be efficiently excited in the circular waveguide 4, and signals can be stably transmitted between the waveguides 2 and 4.