Coaxial Cable Impedance Calculator

Tools - Pcbcupid - Best simplified Coaxial Cable Impedance Calculator

The resistance of a coaxial cable to the flow of electrical signals is known as its coaxial cable impedance.
It is usually given in ohms (Ω) and depends on the physical dimensions of the cable, including the conductor diameter, the dielectric material, and the outer shielding.
In communication systems, a coaxial cable’s impedance has an impact on signal transmission, reflection, and overall performance.

Impedance of coaxial cables is primarily used to minimize signal distortion or loss and to ensure effective signal transmission.
Optimizing the impedance of the cable in relation to the impedance of the transmission lines and connected devices minimizes signal deterioration and enhances signal transfer.

Overall, understanding and optimizing the impedance of coaxial cables are fundamental aspects of designing robust and efficient communication systems. By paying attention to impedance matching, engineers can improve signal quality, enhance transmission efficiency, and ensure the overall success of their communication networks.

Understanding Coaxial Cable Impedance:

“Coaxial cables find extensive application across various fields such as cable television, satellite television, cable modems, and radio frequency (RF) communication systems. An essential attribute of coaxial cables is their impedance, denoting the resistance to the passage of electrical energy.”

Characteristics of Coaxial Cable Impedance:

The impedance of a coaxial cable is established by its physical attributes such as core diameter, insulation, and shielding. Various factors can influence the impedance of a coaxial cable, including:

Core diameter: The size of the central core in a coaxial cable influences its impedance. Generally, a greater core diameter leads to a reduced impedance.

Insulation: The type of insulation material employed in a coaxial cable can influence its impedance characteristics. For instance, a coaxial cable featuring foam insulation may exhibit a lower impedance compared to one utilizing solid insulation.

Shielding: The impedance of a coaxial cable can be influenced by its shielding. For instance, a coaxial cable featuring double shielding might exhibit a lower impedance compared to a single-shielded counterpart.

Measurement of Coaxial Cable Impedance:

Coaxial cable impedance can be measured using a variety of methods, including:

Impedance measurement using a vector network analyzer (VNA).

Impedance measurement using a coaxial cable tester.

Impedance measurement using a potentiometer and an oscilloscope.

Importance of Coaxial Cable Impedance:

The impedance of a coaxial cable plays a crucial role in determining its performance. A high impedance can hinder signal transmission efficiency, whereas a low impedance can enhance it.


  • Telecommunications
  • Broadcasting
  • Computer Networking
  • Test and Measurement Equipment
  • Medical Devices
  • Cable Television (CATV).
  • Radio Frequency (RF) and Microwave Transmission.
  • Computer and Instrumentation Data Connections.
  • Video and Audio Signals.
  • Amateur Radio and Ham Radio.
  • Professional Audio and Video Applications.
  • Industrial and Commercial Applications.
  • Aerospace and Defense.
  • Test and Measurement Equipment.
  • High-Frequency Applications.


In brief, the impedance of coaxial cables plays a crucial role in determining their performance. Familiarity with this characteristic is essential for choosing the most suitable cable for specific applications and guaranteeing its optimal functionality.

An electrical cable known as a coaxial cable is made up of an inner conductor that is encased in a tubular conducting shield and tubular insulating layer. The coaxial cable’s impedance in ohms for a given circuit can be found using this online calculator. To calculate the coaxial cable impedance, cutoff frequency, capacitance, inductance, and propagation velocity, just enter the necessary numbers into the calculator below.

Note : Don’t end with comma ( , )

Dielectric Outer Diameter
Inner Conductor Diameter
Dielectric Constant


\[Z = (138 × log_{10} (d1 / (d2)) / \sqrt{(R)} \\F = 11.8 / (\sqrt{(R)} × π × ((d1 + d2) / 2)) \\T =( (7.354 × R) / (log_{10}(d_1 / d_2)))/0.3048 \\D = (140.4 × log_{10}(d_1 / d_2))/0.3048 \\V = (1 /\sqrt{(R)}× 100\]


  • 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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