[開課學院]: 資電學院
[開課系所]: 電機工程學系
[課程名稱]: 電磁波
[老師名稱]: 柏小松 老師
[開課學期]: 98-1
[類型]: 98-1期中考
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[1] 20%
(a)Explain why waves along a lossy transmission line cannot be purely TEM.
(b)What is mean by the wave impedance of the total field .
When is this impedance equal to the intrinsic impedance of medium ?
(c)Why is a Brewster angle also called a polarizing angle ?
(d)What do we mean when we say that an incident wave has (a)perpendicular
polarization , and (b) parallel polarization ?
[2] 20%
A uniform plane wave with E^ = ax^ Ex propagates in a lossless simple medium
(Er=4,μr=1,σ=0) in the + z direction . Assume that Ex is sinusoidal with a
frequency 100(MHz) and has a maximum value of +0.0001(v/m) at t=0 and z=1/8(m)
(a)write the instantaneous expression for E^ for any t anf z.
(b)write the instantaneous expression for H^.
[3] 20%
Show that the instantaneous Poynting vector of a circularly polarized plane
wave propagating in a lossless medium is a constant that is independent of
time and distance .
[4] 20%
Neglecting fringe field , prove analytically that a 8-polarized TEM wave that
propagates along a parallel-plate transmission line in +z direction has the
following properties: dEy/dx = 0 and dHx/dy = 0 .
[5] 20%
The permittivity of water at optical frequencies is 1.75 εo . It is found
that an isotropic light source at a distance d under water yields an
illuminated circular area of a radius 5 (m). Determine d .
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