# BANDWIDTH OF A DIPOLE ANTENNA

#### muni

Joined Jul 29, 2008
45
THIS IS ALSO A QUESTION FROM GATE PAPERS

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#### DickCappels

Joined Aug 21, 2008
6,532
Why didn't you just type this question in rather than posting a zipped file?

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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.
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Neither do I, but then I do not understand the question, the way it was written.

#### Papabravo

Joined Feb 24, 2006
14,206
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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#### scubasteve_911

Joined Dec 27, 2007
1,203
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

#### muni

Joined Jul 29, 2008
45
I think increasing the diameter increases the bandwidth:

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

#### muni

Joined Jul 29, 2008
45
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.
thank you friend actually i was preparing a list of such doubts and problems. so i made it part by parrt as small copies