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You certainly need an external power aplifying stage (one or several power amplifiers dependent on the power gain of each amp).
What you also need to consider is regulative constraints in addition to battery drain and overall power consumption.
Good luck!
Duh? If you have an existing Tranceiver, and you simply add a power amplifier between the transceiver and the antenna, the receiver portion will stop working (since the transmit amplifier has high loss in the reverse direction). Explain your transcevier a little more.
I have a transceiver that only outputs at 120mW. The device has one output/input for the antenna signal and another for the antenna screen. I would like to amplify when the transceiver is transmitting but not receiving.
If your transceiver chip has a direct antenna connection pin ( doesn't have separated rf in and rf out) you can insert a PA between 2 switches. When you are transmitting, the signal goes through switch1 ->PA-> switch2 to the antenna, when you are receiving the antenna is connected through the switch2-> switch1 to the transceiver.
You have to solve the command signal to switch the direction.
The "antenna boosters" works in a similar way, and they are using a detector on the transcever side. The RF output signal of the transceiver has enough power level to be detected, and drive a comparator, which is used to drive the switches. When the transceiver is not transmitting, the switches are drived on the receiver path.
I have a transceiver that only outputs at 120mW. The device has one output/input for the antenna signal and another for the antenna screen. I would like to amplify when the transceiver is transmitting but not receiving.
FANT, interesting schematic. Are those normal PIN diodes? It looks like you would need a lot of RF to turn these on with self biasing, perhaps 100 mW +, and with the wrong diode could easily be 500 mw. Most unlicensed transmitters only put out 10 mW.
Also, why are the PIN diodes shown back to back? Once one of them starts to conduct, it will short out Rf on either polarity of the sine wave?
Sorry but now I don't remember the exact type, if I remember well they were from macom, but I think any type ( of course forthe proper frequency and power ) will work just fine.
The diodes are back to back to avoid any rectification effect, but it should not happen anyway.
At that time I had no simulation program, the circuit was working fine and so no further investigation.
The circuit ha an attenuation of some 3 dB and it requires at least 100 mW to drive the diodes.
Also the original circuit had some capacitors and inductors because the RF cable is supplying also the power supply for the amplifiers.
Important thing the LNA has to have an output saturated power lower than 0 dBm, to avoid self oscillation of the circuit.
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