Development of semi-empirical design equations for symmetrical three-line microstrip couplers

Semi-empirical design equations for symmetrical three-line microstrip couplers (TMCs) have been developed. The approach is based on dividing the total capacitance of the system into various basic capacitances, which are then calculated empirically and semi-numerically. The numerical results based on these design equations have been found in good agreement with the previously obtained results.