Effects of the Even and Odd Phase Velocity Separation on the Bandwidth Limitation of Nonuniform Line Microstrip Couplers

Abstract

Frequency response of nonuniform line micros trip couplers is given by using a second order theory applied for the even and odd signals which have unequal velocities. This condition leads to finite isolation which becomes worse as the velocity separation increases. A modified structure to equalize the even and odd mode phase velocities is analyzed by a finite difference method applied to hybrid waves.