RF Circuits

Here's a broadband FM RF amplifier using 2SC1971 VHF power transistor. The RF Amplifier PCB layout designed for FM broadband 88-108 MHz using microstripline technique. This 8W RF amplifier circuit provides an appropriate power boost with an input of 500 mW.

RF Amplifier PCB
The PCB outline is 77 x 56 mm use FR-4 double sided photoresist epoxy pcb material for best results.


RF Amplifier Construction
All SMD components are 1206 types. Connect the bottom layer (groundplane) on several points (through via's) with the top layer of the PCB.

Note:
CuL = magnetwire, enameled copper wire
- 1 mm equals approx. to #18 A.W.G
- 0.8 mm equals approx. to #20 A.W.G
- 0,3 mm equals approx. to #28 A.W.G.

• All diameters are measured from the inside of the coils, i.e. 'internal' diameter.
• Make sure to mount the rf-transistor on a appropriate heatsink and use some thermal heatsink compound between the flange of the transistor and heatsink! (Thermal resistance heatsink at least 6°C/W.)
• All parts are soldered directly on the toplayer of the PCB.

Source: Amplifier 6Watt MicroStripline (2SC1971)