Orthogonal-mode coupler

The invention relates to an orthogonal-mode coupler, and belongs to the technical field of couplers. The orthogonal-mode coupler comprises a square waveguide, a side arm waveguide, an impedance adjusting block and a straight arm waveguide, wherein the side arm waveguide and the square waveguide perform electromagnetic coupling through a side arm coupling slit, and the straight arm waveguide and the square waveguide perform electromagnetic coupling through a straight arm coupling slit. According to the invention, a wide-seam structure is adopted to realize impedance matching, complex structures such as an inductance rod, a diaphragm, a gradient impedance transformation segment, which are used for matching, in a traditional orthogonal-mode coupler are omitted, so that the structure of the orthogonal-mode coupler provided by the invention is more compact.