Microstrip Line Calculator

Antennes et capteurs / Calculateur ligne microstrip
Microstrip Line Illustration
Substrate Parameters
Dielectric Constant (εr):
Dielectric Height (h):
Frequency: GHz
Electrical Parameters Physical Parameters
Zo: Ω
Elec. Length: deg

 Width (W):
Length (L):

Description

The microstrip calculator determines the width and length of a microstrip line for a given characteristic impedance Zo and electrical length or vice versa. The substrate parameters εr and h and the frequency of interest are required.

Synthesize

Enter values for Zo and Electrical Length to determine the physical width and length of the microstrip line. Press Synthesize to see the results.

If \( W/h \le 1 \): \( Z_0 = \dfrac{60}{\sqrt{\varepsilon_r}} \ln\!\left( \dfrac{8h}{W} + \dfrac{W}{4h} \right) \)
If \( W/h > 1 \): \( Z_0 = \dfrac{120\pi}{\sqrt{\varepsilon_r}\,\big(W/h + 1.393 + 0.667 \ln(W/h + 1.444)\big)} \)
Effective permittivity: \( \varepsilon_{\text{eff}} = \dfrac{\varepsilon_r + 1}{2} + \dfrac{\varepsilon_r - 1}{2}\dfrac{1}{\sqrt{1 + 12(h/W)}} \)
Phase constant: \( \beta = \dfrac{2\pi f}{c / \sqrt{\varepsilon_{\text{eff}}}} \)
Physical length: \( L = \dfrac{\theta(\pi/180)}{\beta} \) (with \( \theta \) in degrees).

Analyze

Enter values for W and L for a microstrip line to determine its Zo and Electrical Length. Press Analyze to see the results.

Characteristic impedance: same \( Z_0(W/h) \) expressions as above.
Effective permittivity: same \( \varepsilon_{\text{eff}} \) as above.
Electrical length: \( \theta = \beta L \cdot 180/\pi \) (degrees).