[開課學院]: 資電學院
[開課系所]: 電機系
[課程名稱]: 電磁波
[老師名稱]: 柏小松 老師
[開課學期]: 981
[類型]: 98-1期末考
[1](a)Explain why waves along a lossy transmission line can not be purely TEM.
(b)Explain why single conductor hollow waveguides can not support TEM waves.
(c)What does "Matched transmission line" mean ?
(d)Which mode is the dominant mode in a rectangular waveguide if (1)a>b
(2)a<b (3)a=b ∕ y
∕ ↑
∕ │ ∕
∕ │ ∕
∕╴╴╴╴╴╴ │∕
↑│ ← a →│
b │ │ z
↓│ │↗
x ←┴───────┘0
[2]The open-circuit and short-circuit impedances measured at the input
terminals of a lossless transmission line of length 1.5(m),which is less than
a guarter wavelength , are -j54.6(ohm) and j103(ohm),respectively.
(a)Find Z0 and V of the line .
(b)Without changing the operating frequency , find the input impedance of a
short circuited kine that is twice the given length.
[3]The double-stub method is used to match a load impedance 100+j100(ohm) to
a lossless transmission line of characteristic impedance 300(ohm).The spacing
between the stub is 3λ/8 ,with one stub connected directly in parallel with
the load .Determine the lengths of the stub tuners if they are both
short-circuited.
[4]An air-filled rectangular waveguide made of copper and having transverse
dimensions a=7.20(cm) and b=3.40(cm) operates at a frequency 3 (GHz) in
dominant mode. Find (a) fc (b)λg .
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 61.62.104.252