Discussion :: Microwave Communication - Section 1 (Q.No.22)
The width of a radio beam from a 1 m diameter parabolic antenna at 10 GHz is about
Answer: Option C
|Jagriti said: (Dec 23, 2014)|
|What is 140?|
|Lavanya said: (Jan 16, 2015)|
|140 is for antenna factor.|
|Goldy said: (Jul 14, 2015)|
|Please explain in detail.|
|Aravind said: (Aug 1, 2015)|
|Rose said: (Sep 30, 2015)|
Where k is a factor which varies slightly depending on the shape of the reflector and the feed illumination pattern. For an ideal uniformly illuminated parabolic reflector and θ in degrees, k would be 57.3 (the number of degrees in a radian). For a "typical" parabolic antenna k is approximately 70.
|Dhruv said: (Jun 8, 2016)|
Beam width b/w half power points in a parabolic reflector = 70 * (lambda/diameter).
Therefore, beam width b/w first nulls = 2 * half power bw.
Then, we get 140.
|Sankar said: (Oct 14, 2017)|
|I think 140 (λ) /diameter then we get above equation.|
|Ayush Kumar said: (Nov 3, 2017)|
|Yes beam width = 140(lambda)/diameter.|
|Sreeram said: (Feb 15, 2018)|
|Asus said: (Jun 24, 2018)|
|Zecru said: (Dec 19, 2018)|
|We use 70 for the Half Power Beam Width only.|
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