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  #1  
Old 09-27-2008, 08:50 AM
muni muni is offline
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Default BANDWIDTH OF A DIPOLE ANTENNA

THIS IS ALSO A QUESTION FROM GATE PAPERS
PLEASE FIND THE ATTACHMENTS
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File Type: zip antenna banwidth.zip (7.9 KB, 48 views)
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Old 09-27-2008, 09:56 AM
DickCappels DickCappels is offline
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Why didn't you just type this question in rather than posting a zipped file?

========================
If the diameter of a λ/2 dipole antenna is increased from λ100 to λ50, then is
A). Bandwidth increases b) Bandwidth decreases
c). gain increases d). gain decreases
sir I don’t know the formulae to relate between bandwidth , gain and diameter of a dipole antenna.
========================
Neither do I, but then I do not understand the question, the way it was written.
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Old 09-27-2008, 04:16 PM
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Papabravo Papabravo is offline
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In terms of VSWR the response of a dipole is not symmetric about the resonant frequency so the concept of bandwidth is a bit hard to quantify. I think the same is tru for return loss, so how exactly are we defining bandwidth?

I do know that bandwidth, however it is defined, increases with frequency; that is an antenna cut to a given length will have a larger bandwidth if it is cut for a higher frequency.
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Last edited by Papabravo; 09-27-2008 at 07:54 PM.
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Old 09-27-2008, 06:00 PM
pebe pebe is offline
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I think increasing the diameter increases the bandwidth:

http://www.vias.org/radioanteng/rae_03_08.html
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  #5  
Old 09-27-2008, 08:33 PM
scubasteve_911 scubasteve_911 is offline
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I would think that the gain would decrease. It is still a lambda/2 antenna, but of a smaller geometry. Having a smaller antenna with the same lamda/2, I think, would give you much less gain.

Steve
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  #6  
Old 10-03-2008, 05:38 PM
muni muni is offline
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Quote:
Originally Posted by pebe View Post
I think increasing the diameter increases the bandwidth:

http://www.vias.org/radioanteng/rae_03_08.html
sir thank you have given me a food advise. but the book it is too heavy to read and understand this. i feel i don't have that much in depth knwoledge about this. if u have any ready made answer plese pass it on. once again thank you sir
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  #7  
Old 10-03-2008, 05:40 PM
muni muni is offline
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Quote:
Originally Posted by DickCappels View Post
Why didn't you just type this question in rather than posting a zipped file?

========================
If the diameter of a λ/2 dipole antenna is increased from λ100 to λ50, then is
A). Bandwidth increases b) Bandwidth decreases
c). gain increases d). gain decreases
sir I donít know the formulae to relate between bandwidth , gain and diameter of a dipole antenna.
========================
Neither do I, but then I do not understand the question, the way it was written.
thank you friend actually i was preparing a list of such doubts and problems. so i made it part by parrt as small copies
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