| 摘要 |
PURPOSE:To obtain a small-sized both circular/straight polarization type TE21 mode coupler having sufficiently wide band characteristics by branching a TE21 mode wave having two electric field distribution intersected at right angles into groups at the same position on a main transmission line. CONSTITUTION:The mode coupler is constituted by a circular waveguide 41 and eight rectangular waveguides 42 being subtransmission lines, symmetrically arranged on the periphery of the waveguide 41 while keeping 45 deg. around the center axis. The waveguides 42 use their wall surface in the electric field direction in common at the periphery of the waveguide 41 and are arranged like an array and coupled with the waveguide 41 through plural coupling holes 43 having long sides in the pipe axis direction. The intervals of respective coupling holes 43 are decided to about 1/4 the intra-pipe wavelength of the TE21 mode wave and the coupling factor of the coupling holes 43 are distributed, so that another mode wave transmitted in the waveguide 41 is not coupled and only the TE21 mode wave can be branched as a group. |
