Finite difference analysis of cylindrical two conductor microstrip transmission line with truncated dielectrics (Q2564850)

The authors consider the propagation of the quasi-static TEM mode in a transmission line by means of finite difference techniques with the object of reducing coupling between two lines. An approximate boundary condition is developed so as to truncate the finite difference mesh, and a discussion is given about the proper position of the artificial boundary. The methods discussed are applied to two cases, microstrip lines with and without a dielectric notch, and the effects of various parameters such as the dielectric constant of the overlay, that of the notch and its dimensions are indicated. It is suggested how a distortionless line may be obtained, and it is indicated that reduction of distortion may involve increase in coupling.