## Microstrip PCB Impedance Calculator

Microstrip are transmission lines that are routed on the external layers of the PCB which are always routed above a large reference plane on the adjacent layer. As the name suggests microstrip lines are used to convey microwave-frequency signals and RF signals. You can read more about microstrip here.

Calculate the impedance, capacitance, propagation delay, and inductance of a Microstrip Line PCB using this convenient online calculator. Understand the characteristics of your electrical transmission lines and optimize your circuit design.

Trace width
mm
Trace thickness
mm
Dielectric thickness
mm
Relative dielectric constant
mm

Formula

$Z = \frac{87}{\sqrt{e_r+1.41}} * ln \left(\frac{5.98h}{0.8w + t}\right)$
$P = 3.333 * \sqrt{0.475e_r + 0.67} * dimension$
$C = \frac{P}{Z}$
$R = \frac {17.2}{w * t * dimension^2} * 1000$
$L = \frac {P * Z}{1000}$

where :

• Z = Single Ended Impedance
• er = Relative dielectric constant
• h = Trace width
• w = Trace height
• t = Trace thickness
• P = Propagation Delay
• C = Capacitance
• L = Inductance
• R = Resistance
• If the dimension unit is mm then dimension=1
• If the dimension unit is mils then the dimension is 0.0254

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