Frequency-dependent power amplifier modeling and correction for distortion in wideband radar transmissions

This paper presents initial results on utilizing the Volterra series, more specifically the Memory Polynomial model subset of the Volterra series, to model the power and frequency dependent non-linear distortion of a physical power amplifier. This modeling technique is also used to create the necessary digital predistortion so that, when used in series with the same modeled high power amplifier, the overall system acts solely as a linear function of input power within a given bandwidth. This amplifier modeling and associated digital predistortion are especially useful in wideband radar applications, where digital predistortion allows the amplifier to operate at its highest power added efficiency by operating in its compression region while still behaving linearly. As a result, wideband radar waveforms can be generated at high fidelity, maximizing transmission power with the given equipment while maintaining low range sidelobes. The results section of this paper reports preliminary findings.