Analysis of a Two-Section Coupler (Correspondence)

The use of single-section quarter wavelength TEM mode directional couplers having excellent wide-band performance is well known. A method for decreasing the coupling variation with frequency by cascading three quarter wavelength couplers has also been described. The purpose of this note is to analyze, for loose coupling, the behavior of a two quarter wave section coupler and compare the results with a coupler consisting of three sections.