| 摘要 |
PROBLEM TO BE SOLVED: To make an impedance matching state satisfactory over a wide frequency range by making the size of a rectangular cross section part change from a start edge to an end edge in a tapered shape, making characteristic impedance change according to a cosine function defining the tube axial length between start and end edges as a half cycle and also providing a structure in which a tapered shape is represented by a specific functional formula. SOLUTION: In this tapered waveguide 10, the size of a rectangular cross section part changes in a tapered shape in the direction from the start edge to the end edge, the characteristic impedance Z(x) of a position (x) in a tube axial direction changes according to a cosine function defining the tube axial length between the start and end edges as a half period, and also, the tapered shape when an electromagnetic wave length to be used isλs is represented by a function including the expression of [λs/√2√(1+(1-λs4/Z(x)2}]. Also, when the characteristic impedance of the start edge position is defined as Z(0), the tube axial length between the start and end edges is defined as L and the characteristic impedance at the end edge is defined as Z(L), the characteristic impedance Z(x) is represented by Z(x)=(Z(0)+Z(L))/2+((Z(0)-Z(L))/2)cos(πx/L). |
