In a miniature x-ray tube, which may be on the order of approximately 1 mm in
diameter or even less, a high voltage cable is provided in various embodiments
for conducting current to the cathode of the x-ray tube and for conducting high
voltage to the cathode and anode of the tube. In various embodiments of the cable,
two conductors occupy a center region of the cable, packed as closely together
as possible, in various shapes that are compact and present as smooth as possible
an external shape for maximizing dielectric properties against the exterior high
voltage ground, surrounding and generally concentric with the inner conductors.
The inner conductors, which carry high voltage in opposition to the outer ground,
can be in opposed D shapes, coaxial, two flattened conductors side by side, or
simply a pair of cylindrical wires positioned as closely as possible. The space
between the inner conductors and the outer ground can be occupied by a glass insulator,
polymer, successive layers of polymers and adhesive, air, gas, vacuum or other
dielectrics. A partially conductive region can surround the inner conductors.