The electrode analyses of coplanar waveguides

The main purpose of this paper is to study the relationship of CPW´s structural parameters while the benchmark impedance of CPW is 50Ω, and the CPW of LiTaO₃ electro-optical modulator is taken as an example. Conformal mapping theory is used to obtain the numerical relationship of electrode structure, thickness of the substrate and properties parameters, and the results show that the little change of electrode width would affect the CPW remarkably. For the design of the characteristic line impedance of 50Ω CPW, symmetrical structure is a good choice. The formulas and analyses are useful in the design of coplanar waveguides of LiTaO₃ electro-optical modulator.