Abstract
Coaxial cables are electrical cables utilized in communications technology that transmit a radio frequency signal [1]. These cables consist of an inner conductor, a dielectric insulator, and an outer conductor [2–4]. This structure protects the signal from electromagnetic interference and power loss; however, it also inherently inhibits the speed of the signal. This inhibition is determined by the relative electric permittivity of the insulator, a unitless value that describes how easily an electric field can pass through a material. In our experiment, we connected coaxial cables of varying lengths to a signal generator and an oscilloscope to determine the propagation speed and, thus, measure the relative permittivity. Performing a linear regression on the data, we obtained a signal speed of (216±4)×106 m/s with an R-squared value of 0.99 and a P value of 3.40×10−12. Assuming a relative magnetic permeability of µr = 1, we obtained a result of ϵr = 1.9260 ± 0.0002.
