Calculation of Foster-type equivalent network for stripline 45 degrees bend based on novel calculation method of the eigenmode

Foster-type equivalent network for stripline 45 degrees bend of equal or different stripline width is derived based on eigenmode method. The key step is how to calculate eigenmodes of the planar junction of 45° bend up to necessary mode number with exactness. We propose a new idea of three stage cascade-connected stripline configuration and double symmetry with magnetic wall, which is practically carried out with success. The derived equivalent network is applied to the calculation of frequency characteristics and field distribution under the operating.