Power amplifier Fundamentals
• Power basics: power factor, effect of match quality on output power and standing waves • Device technologies (GaN, GaAs, InP, Si, SiGe) and leading commercial/defense suppliers. • Device stuctures: MESFET, pHMET, HEMT, HBT, LDMOS. • Small signal model generation, frequency limits (ft, and fmax); theoretical and practical. • Power Amplifier Stability detection (even mode, odd mode); Freitag detection approach. • Optimum power load estimation, calculation, and simulation. • Load-pull characterization of devices (static, dynamic). • Device characteristics and non-idealities. • Dependence of transistor parameters on drive level. • Large signal models. • Power Amplifier biasing methods. • Bode-Fano limit. • Exercise: small signal model generation.
Conventional and High Efficiency Amplifier Design
• Power amplifier classes A, B, AB, C, and D; concepts, designs, and examples. • Waveform engineering for maximum efficiency. • Class E Switching mode power amplifiers: Concept, Design, Limitations, Maximum Frequency, Exercises, and Examples. • Class F (and F-1) power amplifiers: Concept, Design, Limitations, and Examples. • Comparison of various classes: efficiency, output power, and frequency limitations. • Effects of knee voltage, harmonic terminations, and nonlinearities. • Exercise: High efficiency power amplifier design.
Linearization Techniques and Signal Modulations
• Classical Modulation schemes: AM, FM, PM. • Modern Modulation: FSK, PSK, MSK, BPSK, QPSK, p/4-DQPSK, OQPSK, QAM, etc. • Distortions in power amplifiers. • Harmonic balance and time domain simulations. • Linear/Non-linear Memory effects; electrical and thermal memory effects. • Measures of Distortion: Third order intermodulation, ACPR, NPR, M-IMR, X-parameters. • Linearization techniques: Feed Forward, Predistortion, LINC, Cartesian Feedback, Reflect Forward, Envelope Elimination and Restoration, Cross Cancellation. • Comparison of Linearization Techniques. • Envelope tracking, Polar transmitters. • Real world design examples, challenges, and solutions.
Power Combing, Packaging, and Reliability
• Multistage amplifiers, inter-stage matching. • Push-pull, Balanced amplifiers, and Traveling Wave Combiners. • Power combining techniques (Corporate, Current, Wilkinson, Lange, Branch Line, Serial, Darwish, HiFET). • Package design (ceramic, plastic, PCB, metal composites and alloys). • Thermal management and reliability calculations. • Biasing and transient considerations. • Exercise: calculating required biasing for 20+ year lifetime. • Exercise: Design of a power combiner. • Exercise: Design of a high efficiency power amplifier class F.