Presentation on theme: "MTT 2002 Seattle June 5th S. K. Leong LDMOS and Vdmos 30 - 512 Mhz BroadBand Amps."— Presentation transcript:
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 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)
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.