Electronics and Communication Engineering - Electromagnetic Field Theory - Discussion
Discussion Forum : Electromagnetic Field Theory - Section 1 (Q.No. 10)
10.
A rectangular metal waveguide filled with a dielectric of relative permittivity εr = 4, has the inside dimensions 3 x 1.2 cm, the cut off frequency for the dominant mode is
Answer: Option
Explanation:
for dominant mode.
Discussion:
15 comments Page 1 of 2.
Parvez said:
8 years ago
Vp = c /sqrt(μrεr), here μr =1 ; εr = 4 (given).
So, fc = Vp/2a.
i.e. fc =c/(2a*sqrt(μrεr)).
fc = 2.5 GHz.
So, fc = Vp/2a.
i.e. fc =c/(2a*sqrt(μrεr)).
fc = 2.5 GHz.
Ravi said:
8 years ago
5 GHz is correct answer.
fc = 1.5*10^8 sqrt{(m/a)^2+(n/b)^2} .
Here m=1, n=0 (dominant mode in a rectangular waveguide is TE1,0).
So,1.5*10^8 * m/a = 1.5*10^8 * 1/0.03 = 5*10^9 Hz.
Here a is width.
fc = 1.5*10^8 sqrt{(m/a)^2+(n/b)^2} .
Here m=1, n=0 (dominant mode in a rectangular waveguide is TE1,0).
So,1.5*10^8 * m/a = 1.5*10^8 * 1/0.03 = 5*10^9 Hz.
Here a is width.
John Howard said:
8 years ago
Option A is correct.
λc=2a; fc=v/λc or fc=(c/√(εr))/λc = 2.5 GHZ. v=1.5 10^8 m/s and λc=0.06 m.
λc=2a; fc=v/λc or fc=(c/√(εr))/λc = 2.5 GHZ. v=1.5 10^8 m/s and λc=0.06 m.
(1)
Azar said:
8 years ago
fc = C/2a.
fc = Cut-off Frequency.
C = Speed of Light = 3 * 10^8,
a = Width = 3 cm.
fc = 3 * 10^8 / 2 *3 = 0.5 * 10^8 ==> 5 GHz.
fc = Cut-off Frequency.
C = Speed of Light = 3 * 10^8,
a = Width = 3 cm.
fc = 3 * 10^8 / 2 *3 = 0.5 * 10^8 ==> 5 GHz.
Priti said:
6 years ago
Where c is velocity of light.
a =3,
fc= 3 * 10^8/2 * 3 * 10^-3,
= 5 * 10^9.
= 5 GHz.
a =3,
fc= 3 * 10^8/2 * 3 * 10^-3,
= 5 * 10^9.
= 5 GHz.
Kamlesh said:
1 decade ago
Option A is correct.
Phase velocity is c/2 hence f = c/4a.
Phase velocity is c/2 hence f = c/4a.
Anjli said:
9 years ago
As f = C'/2a.
And C' = C/2 (because Er = 4).
So f = c/4a.
And C' = C/2 (because Er = 4).
So f = c/4a.
Ravi said:
9 years ago
Cut off frequency = c/(2a * sqrt (Er * Ur).
Vinay said:
1 decade ago
Yes option A is correct.
C' = C/2.
C' = C/2.
Ronston said:
8 years ago
What does 'a' stand for? dimension?
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