Microstrip Patch Antenna Calculator

Antennes et capteurs / Calculateur patch
Microstrip Patch Antenna
Substrate Parameters
Dielectric Constant (εr):
Dielectric Height (h):
Resonant Frequency
fr: GHz
Physical Parameters
Length (L):
Width (W):
Input Impedance (Edge)
Result: Ohm

Description

The microstrip patch antenna calculator determines the length L and width W of a rectangular microstrip patch antenna for a given resonant frequency or vice versa. The substrate parameters εr and h are required. If the ratio L/W is close to unity, the radiation pattern will be symmetric but may not provide a reasonable input impedance. This calculator also provides the estimated edge input impedance.

Synthesize

Enter the desired resonant frequency fr to determine the physical length L and width W of the microstrip patch. The input impedance at the radiation edge is also computed. Press Synthesize to see the results.

Width: \( W = \dfrac{c}{2 f_r}\sqrt{\dfrac{2}{\varepsilon_r + 1}} \)
Effective permittivity: \( \varepsilon_{\text{eff}} = \dfrac{\varepsilon_r + 1}{2} + \dfrac{\varepsilon_r - 1}{2}\left(1 + 12\dfrac{h}{W}\right)^{-1/2} \)
Fringing extension: \( \Delta L = 0.412 h \dfrac{(\varepsilon_{\text{eff}} + 0.3)(\dfrac{W}{h}+0.264)}{(\varepsilon_{\text{eff}} - 0.258)(\dfrac{W}{h}+0.8)} \)
Length: \( L = \dfrac{c}{2 f_r \sqrt{\varepsilon_{\text{eff}}}} - 2\Delta L \)
Input impedance (edge feed): \( R_{\text{in}} = \dfrac{90}{\varepsilon_{\text{eff}}^2}\dfrac{L}{W} \)

Analyze

Enter values for L and W for the microstrip patch to determine its fr. The input impedance at the radiation edge is also computed. Press Analyze to view the results.

Effective permittivity: same \( \varepsilon_{\text{eff}} \) as above.
Fringing extension: same \( \Delta L \) as above.
Resonant frequency: \( f_r = \dfrac{c}{2 (L + 2\Delta L) \sqrt{\varepsilon_{\text{eff}}}} \)