回波损耗计算器 — 公式
## 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
- At 1 MHz in copper: skin depth is about 0.066 mm
- At 1 GHz in copper: about 2.1 micrometers
- Conductors for RF need only be a few skin depths thick
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
- At 1 MHz in copper: skin depth is about 0.066 mm
- At 1 GHz in copper: about 2.1 micrometers
- Conductors for RF need only be a few skin depths thick
计算示例
Copper conductor (sigma = 5.8e7 S/m, mu_r = 1) at 1 MHz.
- mu = 1 x 4pi x 10^-7 = 1.2566e-6 H/m
- delta = 1 / sqrt(pi x 1e6 x 1.2566e-6 x 5.8e7)
- = 1 / sqrt(229.37) = 1 / 15.15 = 0.0660 mm = 66.0 micrometers