The answer resides in the discussion of resistivity of metals in the conductors. Because the resistivities of the inner and outer conductor reside in the numerator of the attenuation equation for coaxial cable, the attenuation is proportional to the square root of conductor resistivity. I've been researching attenuation in detail for the last three weeks, and here are some answers I've found. The number of valence electrons in each atom's most distant orbit. The length of the conductor.
Longer length equals more resistance.
The diameter of the conductors. Larger diameters equal less resistance. Even a single, straight conductor exhibits some inductance, which creates a magnetic field. The capacitive properties of a conductor, such as coaxial cable, also increase the opposition to current in a conductor. This opposition to current also is measured in ohms.