Characteristic Impedance Calculator

Select Transmission Line Type: Diameter of Inner Conductor (for Coaxial, or Width for Microstrip) (d/W) in meters: Radius of Outer Conductor (for Coaxial, or Substrate Height for Microstrip) (r/H) in meters: Relative Permittivity (εr) of the Material:

Characteristic Impedance Calculator

This calculator helps determine the characteristic impedance of a transmission line, a critical parameter in RF and high-speed digital circuit design. It calculates impedance based on physical dimensions and material properties of the transmission line structure.

Key Features:

Supports common transmission line types: microstrip, stripline, coaxial
Accounts for dielectric constant and substrate thickness
Provides results in ohms (Ω)
Includes visual diagrams of transmission line geometries

Input Parameters:

Parameter	Description	Example Value
Trace Width	Conductor width (mm or mils)	0.5 mm
Substrate Height	Dielectric thickness (mm or mils)	1.6 mm
Dielectric Constant	Relative permittivity (ε_r)	4.3 (FR4)

Example Calculation: For a microstrip line with 0.5mm trace width, 1.6mm FR4 substrate (ε_r=4.3), the calculator would determine the characteristic impedance to be approximately 50Ω.

Usage Guidance:

Select your transmission line type from the dropdown menu
Enter all required dimensional parameters
Specify units (metric or imperial)
Click "Calculate" to get the impedance value
Use the "Reset" button to clear all fields

Applications: This tool is essential for PCB designers, RF engineers, and anyone working with high-frequency signals to ensure proper impedance matching and minimize signal reflections in transmission lines.

Note: For most accurate results, consult your PCB manufacturer's specifications for exact dielectric properties and fabrication tolerances.