Analysis of stripline circuit consisting of 45 degrees bend and waveguide by mode theory based equivalent network

Various stripline circuits are playing important roles at MIC. These stripline circuits have two dimensionally extended structures, resulting in large effects on their circuit characteristics. Hence, two-dimensional structure must be taken into account for exact calculation of their circuit response. It is well known that stripline can be approximated by planar waveguide, which reduces the stripline circuit to planar circuit. Then, we can derive the rigorous multi-mode equivalent network for these planar circuits by application of mode theory; their frequency characteristics are easily calculated by application of the conventional circuit theory to the thus derived multi-mode equivalent network. Also we can calculate the 2D field distribution at any phase in planar circuit in terms of mode function and so demonstrate the dynamic behavior of field distribution. Finally, frequency characteristics for strip-line circuits are actually calculated by the present theory and their dynamic behaviors of field distribution will be demonstrated at the site.