Real-time load impedance optimization for radar spectral mask compliance and power efficiency

This paper presents a fast optimization algorithm for power amplifiers in radar transmitters based upon a metric designed to assess spectral mask compliance. The search finds the load impedance maximizing the power-added efficiency (PAE) while providing compliance with the assigned spectral mask. Measurement results illustrate consistency in the chosen optimum values of efficiency, while spectral mask requirements are consistently met at the optimum load impedances chosen by the search. This algorithm will allow adaptive radar transmitter amplifiers to quickly adjust their load impedances to change frequency bands of operation, change spectral output properties based on nearby spectrum users, and meet dynamically varying spectral mask requirements.