Design of Wide-Band, Supply Modulated Power Amplifiers Following Linearity Constraints

Supply modulation is a known method to improve the efficiency of amplifiers. But this efficiency improvement often comes at a cost of reduced linearity. This contribution will discuss PA design aspects that affect the linearity of a power amplifier under supply modulating conditions, supply modulation for PAs ranging from X to E-band, and how the bandwidth of practical supply modulators can be expanded. The talk includes a discussion of the predictability of modulated signal performance for compound semiconductor technologies based on typical non-linear commercial transistor models from a practical designer perspective, and compares GaAs and GaN implementations.