A high frequency coax via structure is configured with a stripped semi-rigid cable (no shield), and an inductive compensation loop to mitigate transition discontinuity between that via structure's center conductor and the pad to which the center conductor is connected. The performance of top-to-bottom microwave transitions at high frequencies (e.g., 1 to 12 GHz) for such boards is enhanced. A non-metallized via hole embodiment that is configured with surrounding ground vias provides a greater degree of compensation for connection pads associated with greater capacitance (such as those coupled to a component).