Lk. Yu et B. Rawat, DEVELOPMENT OF SEMIEMPIRICAL DESIGN EQUATIONS FOR SYMMETRICAL 3-LINE MICROSTRIP COUPLERS, IEEE transactions on microwave theory and techniques, 44(3), 1996, pp. 469-472
Semi-empirical design equations for symmetrical three line microstrip
couplers (TMC's) have been developed. The approach is based on dividin
g the total capacitance of the system into various basic capacitances,
which are then calculated empirically and semi-numerically. The numer
ical results based on these design equations have been found in good a
greement with the previously obtained results.