A typical antenna will have an impedance of 75 ohms (or perhaps 50). If you use a transformer with a 1000:1 turns ratio, you will increase the voltage from 10uV to 10mV but since the power is the same, the current must also go down by that factor. That means the source impedance as seen through the transformer will be 75*1000^2 or 75Mohms. That is so high compared to track capacitance on a PCB that you will get no signal at all. Normally you design your PCB tracks for constant impedance to prevent reflections and that will be very important at 2.4GHz due to the short wavelength so you have no choice but to use an LNA as has been said.

Please write more about your problem.

In real systems there will be an amplifier right after the antenna to accomplish this requirement. In simulations, you can just change the units of your variables or scale them as needed.  

I am trying to find out a way in which we can transform a small voltage input to an output of higher voltage without the use of amplifiers. I have heard about impedance transformation. Since power at the output of the antenna is fixed, drawing less current would allow us to provide more voltage. Request you all to give me some suggestion.

It depends on you antenna impedance and your load impedance.  For example, if your antenna is 10 ohms, and you load it with high impedance of infinite ohms, and measure 10 microvolts, then there is no way you can get 10 millivolts just by impedance transformation.  If you are in matched condition, ie antenna impedance is 10 ohms, and load is 10 ohms, still you will get less than 10 microvolts, but you will get maximum power transfer to the load.  The only way to get to 10 millivolts is through some gain device, eg LNA.

The ohm law explains relationship between voltage and current, which is available, it does not amplify. Moreover, even phenomena with change of impedance, voltage/current increase/decrease is one increase other decrease but power does not increase. To increase the power one need to amplify

A very tiny transformer?   What frequency are you working at, and how much SNR loss can you tolerate?   There's a reason the first component in the AFE is an LNA.

I would like to convert the voltage at 2.4GHz. As far as I know, in order to keep the power constant if we reduce the current drawn, we would have a higher volage as Power = Voltage * Current.

Theoretically that's true but at RF, especially as high as 2.4GHz, you are restricted to what rf components and circuits can actually do.  

Power = Voltage * Current, formula decides ideally maximum possible voltage/current. In a matched condition, V = sqrt(P/R) will be the maximum open circuit voltage. In case of loss less line 100% reflection, if incident and reflected wave meets at a point where you can have maximum doubling of voltage.

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Sanat:

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There is no FUNDAMENTAL reason why a 10uV voltage signal at some very low

impedance (let's say 1 ohm) should not be amplified to 10mV of voltage amplitude 

at a much higher impedance; for example, by the use of high-Q resonant circuits. 

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However, even if that should be a PRACTICAL proposition (it is not, especially at

microwave frequencies) what do you expect to do with this signal, now existing at

a very high impedance level? It will be useless.

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You need to think more carefully about what you are really trying to accomplish,

before asking rather silly Alice-in-Wonderland questions.

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Barrie

Maybe you can use transformer to change from low voltage to high voltage. However, Increasing the voltage results in decreasing the current.

use RF Amplifier

You have to use a Low Noise Amplifier. Before that you have to see what is the frequeny of the signal you are recieving from antenna. Depending on this you can decide on amplifier specs.

A typical antenna will have an impedance of 75 ohms (or perhaps 50). If you use a transformer with a 1000:1 turns ratio, you will increase the voltage from 10uV to 10mV but since the power is the same, the current must also go down by that factor. That means the source impedance as seen through the transformer will be 75*1000^2 or 75Mohms. That is so high compared to track capacitance on a PCB that you will get no signal at all. Normally you design your PCB tracks for constant impedance to prevent reflections and that will be very important at 2.4GHz due to the short wavelength so you have no choice but to use an LNA as has been said.

Sanat,

As Barrie generously reminds us, 

"You need to think more carefully

about what you are really trying to accomplish,"

As George wrote, "use an LNA". 

In my world of Amatuer Radio,

we continually use Low Noise Amplifiers 

for signals up into many GHz.  

Frequently we hetrodyne the source signal

down to 100 MHz, then use a LNA.  

These are the standard methods in use by amateur radio experimenters.  These are the starting points to resolve your quest. 

Buena suerte and expand your horizons 

Glen Ellis