How to amplify transmission power of 2.4GHz signal

Hi!
I need to transmit a 2.4GHz signal through a distance of approx 30 feet. But it must pass through five concrete roofs. (Transmitting from the 4th floor to the ground floor of a building). Is a total of 100dB (emitter dB - receiver dB) ok for this?
My emitter power is only 0dB, are there cheap methods to amplify this?

Regards
Mrinal Mani

If the signal modulation is digital AND your receiver sensitivity is sufficiently low FOR certain amount of BER, you can receive the data on the first floor.
2.4GHz can be amplified with a very cheap SMD amplifiers from many manufacturers such as MACOM, Minicircuits,Skyworks etc.There are many others..
But you should take care about "Permissible Legit Power Emission" for your country, it shouldn't be over that limit.

Thanks for the reply!
I found a few RF amplifiers that can amplify up to 30dB easily.
But how to use these in case of a transceiver?
Since the amplifiers will only amplify signal in one direction, how can the same amplifier be used for both transmission and reception? There is only one antenna used alternatively for transmission and reception.

Use a directional antenna with higher gain.

Does your transceiver use full-duplex transmission ? What type of transceiver circuit do you intend to use ?

The transceiver can either transmit or receive at one time. Perhaps something like NRF24L01 or similar.

In this case, you will use a RX/TX switch to insert the ext. PA.When it transmits the signal, the switch will be TX side and PA will also be ON.When RX mode, PA will be OFF and the antenna will be connected to TX/RX I/O.This switch will be controlled simultaneously by RX/TX commutation signal.You can also use an external LNA to amplify incoming signal to improve the RX sensitivity and when TX mode is ON, PA will be connected to antenna ( ext. LNA is OFF ) and when RX mode is ON LNA will be connected to antenna ( ext. PA is OFF ) You can simply improve the transceiver performance by adding an ext. PA and LNA and a high quality and high isolation RF switch.
All you have care about is to pay attention TX RX timing signals ( which also controls the RF switch ) coming from micro-controller otherwise you may loose the stream packets.



Few words for PA..
Look at the specifications of the PA so that it will able to handle the Output Power.If you apply 0dBm for a PA the output power would be 30dBm ( 1W ! ).
Not all the 2.4GHz ISM PAs can carry this power ( caution ) and I don't know this power level is permissible for your country ( warning )

I still don't see why you want to go the difficult way (amplifiers). For this point-to-point radio link, a higher gain antenna would be the much easier way to solve the problem.

Hi!
Thanks a lot for the reply.
As far as directional antenna goes, I dont have the slightest of knowledge of antenna design. It would be great is someone could assist me, but one big constraint is that the antenna must be small. The maximum available height inside the enclosure is just about 25mm. If an antenna with high gain could be fit into this small space, please let me know. I'll be happy to learn something new.

I just looked at some PA and LNA. What I dont understand is that both of them are essentially amplifiers, so why different names? Why not multiplex two PA for RX and TX purpose. Why PA for Tx and LNA for Rx?

Thanks

Hi mrinalmani,

If you are going to use a high gain amplifier and wondering about how to receive the signal from the other device, than I think you can use a circulator. I posted a diagram about the configuration in my mind.

Hope this helps,

Hi.First what do you need it for ? Is the height is only constraint ? IF you are free to use as much area but still want it slim you can use patch array for high antenna gain. As for your question about LNA and PA . Yes both are amplifiers but LNA has lower noise but limited power output, and Power amplifier has high noise but high output. So at the reciever side you have to use LNA just after the antenna,Since the difference between noise and signal you want is really low, you don't want to amplify noise aswell while you are trying to amplify the signal you want. But LNA's lose linearity around 15 dBm output (one db compression point). For higher power levels you cascade a PA to LNA. On the transmit side you already have a signal generator that gives pure signal at your frequency no noise or what so ever.Your only worry is to transmit it to the distance you want. That is why you use PA on transmit side.So you can transmit high power and with the path loss you can still recieve the signal at distant reciever.