Abstract
We report the experimental results of the standing waves in GaAs coplanar waveguides at frequencies up to 20.10 GHz with different terminations (open, short, and 50 Ω) by a new electro-optic probing technique. The effective refractive indices from 4.11 to 20.10 GHz are presented and compared with theoretical values. Dispersion of coplanar waveguide in that frequency range is shown to be negligible.