In this paper, the influence of the position of the metallic signal strips on the cutoff characteristic of dominant mode and field patterns in a novel rectangular-shaped microshield lines with dual signal lines are calculated by edge-based finite element method. The cutoff wavelength can be adjusted by changing the dimensions of the metallic signal strips as well as by adjusting their positions. Field patterns of the dominant mode and the first higher-order mode for different dimensions and the dielectric constant of dielectric substrate are also illustrated. Numerical results provide an extension to the existing design data of rectangular-shaped microshield line and are considered useful in practical applications.