On-wafer microwave characterization and uncertainty evaluation of two-port coplanar waveguide (CPW) high impedance nanodevices are proposed. The test devices are manufactured with resistive metallic nano-films integrated in tapered CPW structures. Microwave conductance in the range 100-500 mu S associated to parallel capacitances in the order of hundreds aF are exemplary shown up to 20 GHz. The uncertainty corresponding to the post-calibration residual errorsterms is provided. In addition, a sensitivity analysis investigating technological process variability using FEM-based EM modelling is considered.