A novel broadband through silicon via (TSV) interconnect is proposed for three dimensional coplanar waveguide (CPW) transition. Simple truncation of CPW ground plane in the transition region to the via size improves return and insertion loss of the three dimensional CPW transition. The characteristic impedance in the TSV interconnect is evaluated and optimum position of GND via hole is found by three dimensional electromagnetic simulations. Performance of the back-to-back novel TSV interconnect is characterized by simulations and measurements. The return loss of the novel TSV interconnect is below 20 dB over 88 % of a 50 GHz bandwidth. The return loss is improved by 10 dB and the insertion loss is well behaved response up to 25 GHz and better than 0.2 dB/mm across the 50 GHz band.