In this live-streamed exercise in the "Electromagnetic Compatibility" module, we are discussing the solution of task 15 of our exericse booklet on shielding.
An electromagnetic wave with an amplitude of E = 1 V/m and a frequency of f = 10 MHz impinges on a copper wall. The source of the field is located at a distance of r = 10 m from the wall.
How large are
a) the skin depth δ inside the metal,
b) the wave impedance Z_m inside the metal,
c) the transmission coefficient t_am from air to metal,
d) the amplitude of the current density J_0 on the surface of the copper wall, and
e) the current I flowing on a wall with a width of 1 m?
print version: https://cloud.ovgu.de/s/PTfXwD74kwbYaYM
smartphone version: https://cloud.ovgu.de/s/KKoQeBJdimFzwWg
https://cloud.ovgu.de/s/rmDBzgykbsEdkeS
https://cloud.ovgu.de/s/NoNnxmwaysQCJ9T
clear all
clc
E=1
f=10e6
r=10
c=3e8
lambda=c/f
r_0=lambda/2/pi
mu=4pi1e-7
kappa=58e6
delta=1/sqrt(pimukappaf)
delta1e6
kappa
omega=2pif
epsilon=8.854e-12
omegaepsilon
Z_m=sqrt(1jomegamu/(kappa+1jomegaepsilon))
Z_m=sqrt(1jomegamu/kappa)
Z_m=(1+1j)/kappa/delta
Z_m1e3
Z_a=377
t_am=2Z_m/(Z_a+Z_m)
r_am=(Z_m-Z_a)/(Z_m+Z_a)
t_am=1+r_am
E_m=t_amE
J_0=kappaE_m
I=J_01*delta
00:00 Welcome and explanation of the task
04:39 Skin depth
17:25 Wave impedance
29:31 Transmission coefficient
45:17 Current density and current on the wall
Original chat from Twitch:
kiskiller0: is this university physics ?