engineers and technicians will never have the need to calculate the capacitance, inductance, or impedance of a coaxial
cable since they are usually designing systems using well-defined components that are manufactured to exacting specifications.
Students, hobbyists (Ham radio operators), and research types are probably the ones most likely to actually plug
numbers into a calculator. For those people, I present these equations.
Click here for popular coax cable properties.
||Most often used braided flexible (shown at left) and solid tube semi-rigid (shown at right) types are listed
Capacitance (C) =
Inductance (L) =
Impedance (Z0) =
(c = speed of light in a vacuum)
Cutoff Frequency =
Reflection Coefficient =
Peak Voltage =
Cable attenuation is the sum of the conductor losses and the dielectric losses per the following equations.
(NOTE: f=frequency in GHz)
ρr = 1 for copper, 10 for steel
d = outside diameter of inner conductor in inches
D = inside diameter of outer conductor in inches
S = maximum voltage gradient of cable insulation in volts/mil
ε = dielectric constant
εr = relative dielectric constant
K = safety factor
f = frequency in MHz
ρrd = inner conductor material resistivity relative to copper
ρrD = outer conductor material resistivity relative to copper
δ = loss tangent