Asymmetric microstrip gaps mounted inside a ground cylindrical surface

Accurate characterization of cylindrical microstrip gap discontinuities is crucial for the design of the circuits including them. In the past, considerable work has been done analyzing a variety of microstrip gap discontinuities on planar and curved substrates. However, the related studies on the asymmetric gap discontinuities mounted inside a grounded cylindrical substrate are still scant in the open literature. In this paper, a full-wave spectral-domain approach is used to analyze such asymmetric gap structures. To obtain a numerical solution, the entire-domain sinusoidal functions are used to represent the traveling-wave mode of the strip current and piecewise sinusoidal (PWS) functions are added in the vicinity of the gap to model the current disturbance due to the structure discontinuity. The dispersion characteristics of the frequency-dependent S-parameters and the gap equivalent capacitances for various microstrip width ratios are presented and discussed.