Coaxial through silicon via (TSV) technique allows reduction of high frequency loss due to conductivity in silicon substrate and flexibility in impedance by controlling the ratio of shield to center radii. For the first time, we measured and analyzed the high-speed channel performance of coaxial TSV. This letter presents the measurement results of the fabricated test vehicle in S-parameter and eye-diagram. The eye-diagram measurement results prove that coaxial TSV is capable of supporting signal transmission up to bit rate of 30 Gbps. The equivalent circuit model is suggested and experimentally verified by S-parameter comparison. Furthermore, the superiority of coaxial TSV over conventional TSV is confirmed by comparison of S-parameter results from equivalent circuit model simulation.