- #1
derek l
Homework Statement
An E field with f = 2.45*10^9 Hz passes through a material with the following properties
e_r = 10
u_r = 1
sigma = 1 (S/m)
The Incident E field has peak magnitude of 300 V/m at the air to surface boundary.
(a) *solved* Find the incident power density at the material surface
p_avg = 1/2*Real[E×H]
because η_o = 120π in free space
p_avg = (0.5)(300)(0.795) ≅ 120 W/m^2 similarly 300^2/2*η_o *correct*(b) Calculate transmitted power into the material at the surface boundary
Homework Equations
loss tangent of material = 0.6329 rad^-1 = 18°
The Attempt at a Solution
η = 106e^(j*18°)
H = 0.795e^(-αz)
E = H*η = 84.25
E = 84.25e^(-αz)
p_avg = 1/2*Real[E×H] = 33.48 *incorrect*