1. What is Coaxial Capacitance?

Coaxial capacitance refers to the capacitance per unit length of a coaxial cable, which consists of an inner conductor surrounded by a tubular insulating layer and an outer conductor. It's an important parameter in transmission line design and signal integrity analysis.

2. How Does the Calculator Work?

The calculator uses the coaxial capacitance formula:

Where:

• \( C \) — Capacitance per unit length (F/m)
• \( \epsilon \) — Permittivity of the dielectric material (F/m)
• \( D \) — Outer conductor diameter (mm)
• \( d \) — Inner conductor diameter (mm)

Explanation: The formula calculates the capacitance per unit length between the inner and outer conductors of a coaxial cable, which depends on the dielectric material properties and the geometric dimensions.

3. Importance of Coaxial Capacitance Calculation

Details: Accurate capacitance calculation is crucial for designing transmission lines, predicting signal propagation characteristics, impedance matching, and minimizing signal distortion in high-frequency applications.

4. Using the Calculator

Tips: Enter permittivity in F/m, both diameters in mm. All values must be valid (positive numbers) and the outer diameter must be greater than the inner diameter.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range of coaxial capacitance values?
A: Typical values range from 50-100 pF/m for standard coaxial cables, depending on the dielectric material and dimensions.

Q2: How does dielectric material affect capacitance?
A: Materials with higher permittivity (ε) increase capacitance, which affects signal propagation speed and impedance.

Q3: Why is the natural logarithm used in the formula?
A: The logarithmic relationship comes from the cylindrical geometry of coaxial cables, where the electric field varies inversely with radius.

Q4: How does capacitance affect signal transmission?
A: Higher capacitance increases signal attenuation and reduces propagation velocity, which can limit bandwidth and maximum cable length.

Q5: Can this formula be used for other cylindrical capacitors?
A: Yes, the same formula applies to any concentric cylindrical capacitor configuration, not just communication cables.