Calculadora de Perda de Retorno
Calcule a perda de retorno em sistemas de RF para avaliar a qualidade da correspondência de impedância.
Copper = 5.8e7, Aluminum = 3.77e7
1 for non-magnetic materials
Profundidade de Penetração
0.000066 m
Skin Depth vs Frequency
Formula
What is Skin Depth?
Skin depth is the distance into a conductor at which the current density drops to 1/e (about 37%) of its surface value. At high frequencies, current flows mostly near the surface.
Formula
delta = 1 / sqrt(pi x f x mu x sigma)
Where f is frequency, mu is permeability (mu_0 x mu_r), and sigma is conductivity.
Practical Impact
Exemplo Resolvido
Copper conductor (sigma = 5.8e7 S/m, mu_r = 1) at 1 MHz.
- 01mu = 1 x 4pi x 10^-7 = 1.2566e-6 H/m
- 02delta = 1 / sqrt(pi x 1e6 x 1.2566e-6 x 5.8e7)
- 03= 1 / sqrt(229.37) = 1 / 15.15 = 0.0660 mm = 66.0 micrometers
Perguntas Frequentes
Why does skin depth matter?
It determines the effective cross-section of a conductor at RF frequencies. Thicker conductors waste material beyond a few skin depths.
How does skin depth affect PCB traces?
At GHz frequencies, only a thin layer of copper carries current. Surface roughness and plating quality significantly affect loss.
What about magnetic materials?
Magnetic materials (mu_r > 1) reduce skin depth dramatically, which is why they are used in shielding applications.
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