The Design of Discrete N-Section and Continuously Tapered Symmetrical Microwave TEM Directional Couplers

A method is presented for the computer-aided design of either N-section discrete or continuously tapered symmetrical microwave couplers. The coupling distribution function k(x) is parametrized in the form k(x, p¯), and a special optimization process (of the generalized Remez type) is used to determine the set of parameters p¯ which produce an optimum power coupling response. Standard parametric forms based on an approximate Fourier analysis as well as more general spline parametric forms for k(x, p¯) are developed and illustrated.