An interposer test vehicle with TSVs(through-silicon vias) and two redistribute layers(RDLs) on the top side for 2.5D integration was fabricated and high-frequency interconnections were designed in the form of coplanar waveguide(CPW) and micro strip line(MSL) structures. The signal transmission structures were modeled and simulated in a 3D EM tool to estimate the S-parameters. The measurements were carried out using the vector network analyzer(VNA). The simulated results of the transmission lines on the surface of the interposer without TSVs showed good agreement with the simulated results, while the transmission structures with TSVs showed significant offset between simulation and test results. The parameters of the transmission structures were changed,and the results were also presented and discussed in this paper. An interposer test vehicle with TSVs (through-silicon vias) and two redistribute layers (RDLs) on the top side for 2.5D integration was fabricated and high-frequency interconnections were designed in the form of coplanar waveguide (CPW) and micro strip line The signal transmission structures were modeled and simulated in a 3D EM tool to estimate the S-parameters. The measurements were carried out using the vector network analyzer (VNA). The simulated results of the transmission lines on the surface of the interposer without TSVs showed good agreement with the simulated results, while the transmission structures with TSVs showed significant offset between simulation and test results. The parameters of the transmission structures were changed, and the results were also presented and discussed in this paper.