[試題] 100上 江簡富 電磁學二 第二次小考

[nihility7893 (千本櫻)]

課程名稱︰電磁學二
課程性質︰必修
課程教師︰江簡富
開課學院：電資學院
開課系所︰電機系
考試日期（年月日）︰2011/12/13
考試時限（分鐘）：2:20 ~ 3:20
是否需發放獎勵金：是
（如未明確表示，則不予發放）

試題 :

                     2011 Fall Electromagnetics II - Quiz II

Each problem is 50 points, and the final score will count on the highest

2 scores from 4.


Problem 1

For a transmission line of characteristic impedance 50 Ω , terminated by a

load impedance (50 + j50)Ω , find the following quantities by using the Smith

chart : (a) reflection coefficient at the load ; (b)SWR on the line;

(c)the distance of the first voltage minimum of the standing-wave pattern

from the load;(d)the line impedance at d=0.15λ;and (f)the location nearest to

the load at which the real part of line admittance is euqal to the line

characteristic admittance.


Problem 2

A transmission line od charateristic impedance 50Ω is terminated by a certain

load impedance. It is found that SNR on the line is equal to 4.0 and that

first voltage minimum of the standing-wave pattern is located to be a at 0.2λ

from the load.Using the Smith chart , determine the location nearest to the

load and the length of a short-circuited stun of characteristic impedance

50Ω connected in parallel with the line required to achieve a match between

the line and the load.


Problem 3

The input impedance of a lossy line of length 50m is measured at a frequency

of 200 MHz for two cases : with the output short-circuited,it is (10 + j49)Ω,

and with the output open-circuited,it is (10-j49)Ω.Find :

(a) the characteristic impedance of the line ,

(b) the attenuation constant of the line ; and

(c) the phase velocity in the line,

assumeing its approximate value to be 1.75 X 10^8  m/s.



Problem 3

For the lossy transmission line system shown in Fig.1 , fine (a) the

time-average power flow at the input end of the line ;

(b) the time-average power delivered load; and

(c)the time-average power dissipated in the line





                           9.25λ

                   ←─────────→
                  ╭╮────────╭╮
              ┌─││                ││─┐
              │  ╰╯────────╰╯  │
─           ──      ─                  ──  ─
Z_g=(30-j40)│  │     Z_0=50Ω           │  │ Z_R =(30+j40)Ω
         Ω  ──    α=0.002NΡ/λ        ──
─            │                            │
V_g=100V      ○                            │
              │  ╭╮────────╭╮  │
              └─││                ││─┘
                  ╰╯────────╰╯
                   d=1       ←        d=0


                         Fig. 1





推 effect511   :是江簡富?
→ nihility7893:打錯~ sorry
※ 編輯: nihility7893    來自: 140.112.25.106       (01/16 08:40)
→ gm800313    :這不是江簡富班的小考吧
→ nihility7893:我再問一下我同學~
推 ym920823    :的確不是