US Patent 7180009 Transmission line with stripped semi-rigid cable

A high frequency coax transmission line structure is configured with a stripped semi-rigid cable (no shield). The stripped cable is inserted lengthwise into a metallized grounded slot formed in a printed wiring board. The dielectric barrel of the stripped cable contacts each of the elongated side and bottom walls of the slot. An exposed portion of center conductor at each end of the cable lays tangent on a corresponding one of connection points (at each end of the slot). The structure reduces loss for long transmission line lengths, and fixes the mounting depth and routing for a consistent transition. Inductive compensation can be provided at the connections point at each end of the slot to mitigate transition discontinuity.