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Transmission Line Parameters of a Coaxial Cable




Inner Conductor Radius (a)

Outer Conductor Radius (b)

Conductor Material

Conductivity: σ =


Dielectric Material

Relative permittivity: εr =


Inductance per unit length

 μH per 

Capacitance per unit length

 pF per  

Resistance per unit length

 mΩ per 

Characteristic Impedance


coaxial cable transmission line equations

Instructions: Enter the frequency, inner conductor radius and outer conductor radius. If you want to specify a conductor other than copper, choose "custom" and specify the conductivity of the conductor material. If you want to specify a dielectric other than air, choose one of the other optional materials or choose "custom" and specify the relative permittivity of the dielectric. Click the "Calculate" button to show the calculated transmission line parameters. Per-unit-length parameters are "per meter" if the inner conductor units are cm or mm. They are "per foot" if the inner conductor units are inches or mils.

Note: All materials are non-magnetic (i.e. μ = μ0). Dielectric losses are not modeled. Low-frequency resistance calculations do not include the resistance of the outer conductor, which is both small and a function of the thickness. High-frequency resistance calculations include the resistance of both conductors.

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