Figure A

Figure A is the schematic of the microstrip single stage RF amplifier. The amplifier is based on the M/A-Com LF2810A MOSFET. The transistor is actually a 10 watt, 28 volt part, but provides adequate gain for this application at 12 VDC. The amplifier provides greater than 40% efficiency at the desired output power. Trimmer capacitors are used for input and output matching. Output power is adjusted by a trimpot which sets the gate bias voltage.

Figure B

Figure B is the layout for the microstrip circuit board. The board material is 0.030 inch Duroid. The circuit board is compression soldered onto a similarly sized copper heat spreader. The board and spreader are milled and drilled to accept the flange-mount transistor.

About LF2810A:

LF2810A is a RF Power MOSFET Transistor 10W, 500-1000MHz, 28V.

LF2810A Features:

• N-Channel enhancement mode device
• DMOS structure
• Lower capacitances for broadband operation
• Common source configuration
• Lower noise floor
• Applications – Broadband linear operation 500 MHz to 1200 MHz

Download LF2810A RF Power MOSFET Datasheet:

LF2810A Datasheet

1 file(s) 136.42 KB

Download Datasheet

source: http://www.ham-radio.com/wb6zsu/components/exciter/exciter_mods.html

2SC2539 is a silicon NPN epitaxial planar type transistor designed for RF power amplifiers in VHF band mobile radio applications.

FM RF Amplifier Circuit Diagram:

Coil Specifications:

L1: 2T Coil diameter:4mm
L2: in series 6pcs Toroidal ring
L3: 4T Coil diameter:10mm
L1: 3T Coil diameter:10mm

FEATURES

• High power gain: Gpe >= 14.5 dB at Vcc=13.5V, Pout = 14W and f=175MHz
• Emitter ballasted construction and gold metallization for high reliability and good performances
• Low thermal resistance ceramic package with flange
• Ability of withstanding more than 20:1 load VSWR when operated at Vcc=15.2V, Pout=18W, f=175MHz, Tc=25⁰C

Download the datasheet of RF Power Transistor 2SC2539 from te following link:
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