Guiding characteristics of a coplanar waveguide with periodic variation in strip width

In this paper, we present a systematic investigation of the guiding characteristics of a coplanar waveguide with periodic variation of the line profile. Based on the method of the effective dielectric constant (EDC), simple formulas are obtained and the numerical results are expressed in the form of the Brillouin diagram, with both phase and attenuation constants included. Furthermore, the scattering of guided waves by a periodic structure of finite length is analyzed both theoretically and experimentally with results in excellent agreement, and the scattering results tally very well with the dispersion characteristics. Thus, the method presented in this paper provides not only a clear physical picture for understanding the wave phenomena involved but also a simple yet accurate design criterion for practical considerations.