Achieving desired characteristic impedances in customized coplanar waveguide transmission line design

Coplanar waveguide (CPW) transmission lines are valued for their planar design, low radiation, and minimized signal loss, but controlling their characteristic impedance remains a challenge. This study employs the Taguchi method, a statistical approach, to optimize the characteristic impedance by adjusting eight control factors: track width, track thickness, gap width, dielectric height, backplane thickness, conductor material conductivity, dielectric conductivity, and operational frequency. The analysis evaluates these factors across three levels to find optimal conditions, with dielectric height and track width identified as most influential. Additional assessments using main effect screening, Analysis of Variance (ANOVA), and multivariable linear regression validate the Taguchi method's effectiveness. The results of this effort encompass a distributed resistance of 133.69 Ω/m, a distributed inductance of 2.6676E^-7H/m, a shunt conductance of 2.8880E^-16 S/m, a capacitance of 7.4103E^-11 F/m, a propagation constant of (1.1141 + 279.36i) m^-1, and a characteristic impedance of (59.999 - 0.23928i) Ω. A CPW transmission line with a characteristic impedance of 60 Ω was successfully designed and simulated using COMSOL Multiphysics, showing promising results for efficient CPW designs tailored to specific applications. The paper describes•Applied the Taguchi method to assess control factors that affect the Characteristic Impedances of the coplanar waveguide Transmission Lines.•Conducted additional validations with ANOVA and regression analysis.•Simulated designs based on optimized parameters using COMSOL Multiphysics.