| 摘要 |
PURPOSE:To obtain a shared branching filter for orthogonal double polarized wave, by forming a tapered waveguide with a square waveguide and varying the taper in a curve. CONSTITUTION:The higher order mode produced from a square tapered waveguide 3 is equal to a TM2 (square shape) mode and opposite to a TM11 (round shape) mode of a round waveguide, and the cutoff frequency fCTM21 is equal to fCTM21=335.19/a2 (GHz). While the cutoff frequency fCTE10 of the basic wave TE10 (square shape) mode of the square waveguide is equal to 149.9/a2 (GHz). Accordingly fH/fL is set at 2.236-fold value (2.08 with the round tapered waveguide) to realize a wide band. At the same time, a change of position is reduced for the equivalent reflective surface of a tapered waveguide 3 to the wave within the band fL by varying the taper in a curve. As a result, the optimum position has no big change by the frequency for a coupling hole 2 for the branching of the wave of fL. Thus the brahching filter characteristics can be improved over a wide range for the wave of fL. |
