ANALYSIS OF MICROWAVE PLANAR CIRCUITS BY NORMAL MODE METHOD.

In this paper electromagnetic fields in the planar circuit and transmission lines connected to the planar circuit are expressed in a series of eigenmodes and the impedance matrix viewed from the transmission lines toward the planar circuit is calculated by connecting terms of these eigenmodes. The impedance matrix is easily solved by using the approximation instead of solving infinite-dimensional algebriac matrix equations. An equivalent circuit for the microwave planar circuit is derived from this impedance matrix. The frequency characteristics of the square-shaped circuits to which one or two transmission lines are connected are derived.