JPS5781702A - Flexible waveguide for electromagnetic wave - Google Patents

Abstract

PURPOSE:To increase the band of using frequency, by forming a section of a flexible waveguide for electromagnetic wave into a cocoon shape and selecting the coefficient of an equation expressed by a prescribed relational equation within a prescribed range. CONSTITUTION:The diagram shows a section of the corrugation of a long flexible waveguide having a ridge, and this section 4 shows a cocoon shape. This shape can be regarded approximately as a cord-type linear shape, and accordingly (x<2>+y<2>)<2>+(4b<2>-a<2>)(x<2>+y<2>)=4b<2>x<2> is generally satisfied in terms of a relational equation of the x-y orthogonal coordinates. In the above-mentioned equation, the coefficients (a) and (b) plus the range of K(=b/a) is regulated to 0.40< K<0.45 and 1.00<2a/A<1.08 respectively (A: long side length of a square waveguide to be connected). As a result, the usable frequency band is increased although the connection to a square waveguide is taken into consideration, and at the same time the loss of transmission is reduced.