The dispersion characteristics of the effective dielectric constant and the characteristic impedance of a superstrate-loaded cylindrical microstrip line are examined. Numerical results of fundamental and higher order modes are computed using a spectral-domain integral equation formulation in conjunction with the method of moments. Entire-domain sinusoidal functions are employed for microstrip current expansions to obtain convergent results with relatively few terms. The results show that the effects of the cover layer on the dispersion curves for the narrower strip are more appreciable than for the wider strip.
Microwave and Optical Technology Lett., 16(6): 385-389