290 likes | 448 Views
MTT 2002 Seattle June 5th S. K. Leong. LDMOS and Vdmos 30 - 512 Mhz BroadBand Amps. 30 - 512 Mhz Broadband Amps. A. 30 - 512 Multi-octave Military Amplifiers covering tactical ground, air, civil and those of allies. B. Polyfet Technical Bulletins Different Output Power and Gain
E N D
MTT 2002Seattle June 5th S. K. Leong LDMOS and Vdmos 30 - 512 Mhz BroadBand Amps
30 - 512 Mhz Broadband Amps • A. 30 - 512 Multi-octave Military Amplifiers covering tactical ground, air, civil and those of allies. • B. Polyfet Technical Bulletins • Different Output Power and Gain • 28V and 12.5V voltage supplies • C. 4:1 Broadband matching • Variable transformation ratio to match transistor Zin • Small physical size. • D. Computer Simulation results
Design Considerations • Load line required by device changes with frequency • Load Pull techniques not practical for high power and low frequencies. • Computer simulation using Spice model is preferred. • 4:1 Most practical transformer for broadband • Use effective inductance of coaxial transmission line as the inductive component in the PI matching network. Keep overall physical dimension small. (A lumped 4:1 replacing a 4:1 plus a low pass network)
4:1 with embedded lump matching • At low freq., matched to load line rather than impedance
Picture of TB-160 Link to Application Note TB160
TB-160 Sim. Schematic Link to AWR simulation file
Simulators • This circuit has been successfully simulated using • AWR Microwave Office 2002 Ver 5.5 • Agilent ADS • Results are comparable between simulators
Conclusion • Achieved multi octave broad banding with both Ldmos and Vdmos at high RF Output Levels • Good correlation between Actual Measurements to Simulation using Polyfet Spice Models • Small physical size matching network made possible by using inherent inductance of coaxial transmission lines along with shunt capacitance. • Transistor impedance changes with frequency.