Coaxial Cable Impedance Formula

Coaxial Cable Impedance is the ratio of voltage to current in a cable of infinite length. It is measured in terms of ohms. Majority of the telephone industry, all the major manufacturers of radio, television, radar, navigation aids, fire control, aircraft, shipbuilding, underwater sound, and many other types of transmitting equipment use coaxial cable. Make use of the coaxial cable impedance formula given below to find the impedance of the coaxial cable.


Z = (138 × log10 (d1 / (d2)) / √(R)
F = 11.8 / (√(R) × π × ((d1 + d2) / 2))
T =( (7.354 × R) / (log10(d1 / d2)))/0.3048
D = (140.4 × log10(d1 / d2))/0.3048
V = (1 / √ (R)) × 100


Z = Impedance
d1 = Dielectric Outer Diameter
d2 = Inner Conductor Diameter
R = Dielectric Constant
F = Cutoff Frequency
T = Capacitance
D = Inductance
V = Velocity of Propagation

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The uses of coaxial cable extend to any application in which signal loss and attenuation must be kept to a minimum, or in which the elimination of outside interference is important. The above coaxial cable impedance formula will be a helpful one for the professionals in the radio and television industry.

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