Dear Dheeraj,

welcome,

I would like to discuss the matter with you. In order to further develop tha above formula one has to assume that the antenna is transmitting antenna and its input power is Ps. This power will be increased by the gain of antenna since it will be radiated according to the directivity of the antenna.The power radiated from the antenna the radiated power is called the effective radiated power Pefrad. The Pefrad= Aa Ps, where Aa is the antenna gain. assuming the noise generated is antenna and input to it =N,

Then the S/N = Aa Ps/ N, this can be substituted in the Shanon Formula to relate C/B to the antenna gain.

It is clear the antenna gain plays an important role in boosting the S/N ratio.

Best wishes

Respected Abdelhalim Zekry Sir,

Thank you very much for your reply. I am trying to relate S/N (signal to noise ratio) and Gain of antenna from Shannon formula

C = B log2 ( 1+ S/N)

C/B = 3.32 log10( 1+S/N)

C/B = (3.32/10)10 log10(1+S/N)

if S/N>1

C/B = (3.32/10)10log10(S/N)

since 10log10(S/N)= (S/N) dB

so C/B= (3.32/10) (S/N)dB

S/N = Aa Ps/N

Aa = gain of antenna

Ps= input power to transmitting antenna

so C/B= (3.32/10) (Aa Ps/N)dB is this right sir?

Sir, if I want to design an antenna of very high signal to noise ratio (S/N = 200 dB) is this practically possible? What should be the precautions for designing this antenna? what will be gain of this antenna?

The first part is right.

The second part you can estimate the highest possible gain of the antenna which may me a parabolic reflector with large size for microwave frequencies. And then the transmit power which may be as high as 1 kw and the noise that can be of equivalent temperature say of 100 K. I think in geosynchronous satellite communication system one can appraoch this value at the ground transmitting station. You can your self investigate the practicality of the given value.

That is where it is required.

Best wishes