There are chips in cell phones that amplify a weak high-frequency signal by power, and one of these chips is RF3140. This chip was used in old cell phones, today it is no longer in production, but you can still buy it
Based on this microcircuit, you can assemble a microwave power amplifier for the frequency ranges: 824-849 MHz (GSM850), 880-915 MHz (EGSM900), 1710-1785 MHz (DCS 1800), 1850-1910 MHz (PCS1900). Power supply from 3 to 5.5 V. The output power with a power supply of 3.7 V at a frequency of 1785 MHz is 2.2 W with a current consumption of 1.1 A. The output power can be adjusted.
A weak DCS / PCS signal is supplied to pin 1, from pin 11 this amplified signal goes to the antenna. A weak GSM/EGSM signal is fed to pin 7 and from pin 9 to the antenna. Pin 2 is used to switch ranges. At a high level, DCS/PCS will be connected, at a low level, GSM/EGSM. According to the diagram, the DCS/PCS range is connected. Pin 3 is connected to the plus through a resistor, pin 4 is the plus of the power supply. Pin 5 is used to adjust the transmitter output power. A signal from the DAC is fed to pin 6, but it is not used in the diagram.
The photo shows the pinout. All the pins that are not indicated are the negative pin, including the large rectangle, to which I connected the negative power supply.
Since I do not have a weak signal source for these frequencies, I connected a 4 cm long wire to pin 1 to generate a signal and test the microcircuit. At frequencies in the 1710-1910 range, the microcircuit will begin to generate a signal that can be taken from pin 11. I connected a 3.5 cm antenna to this pin through a 2.5 V*150 mA incandescent lamp. The microcircuit will heat up with such a non-standard connection, part of the power does not go to the antenna but dissipates as heat. The microcircuit must be installed on a radiator through heat-conducting paste.
I adjusted the power to the minimum with a trimmer resistor...
... and to the maximum. With proper connection of this microcircuit, and this is the installation of capacitors on the power supply, input-output matching, you can assemble a microwave power amplifier for various applications.
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