Improved estimation for Saleh model and predistortion of power amplifiers using 1-dB compression point

Abstract

This paper proposes an improved estimation approach for modelling RF power amplifiers (PAs) using the Saleh behavioural model. The proposed approach is appropriate for solid-state PA technologies. The 1-dB compression point of the PA is included in the estimation approach to improve the estimation of the Saleh coefficients. Thus, expressions are derived to describe the relationship between the parameters of the Saleh model and the manufacturing specifications of PAs: gain (G), third-order intercept point (IP(3)) and 1-dB compression point (P(1dB)). This method is a simple estimation of a memoryless amplitude-to-amplitude (AM/AM) nonlinearity to benefit RF designers evaluating the PA distortion using the PA parameters: P(1dB), G, and IP(3), before conducting experimental validation. The linearisation method using digital predistortion (DPD) is derived as a function of G, IP(3), and P(1dB), for mitigating the AM/AM nonlinear distortion. Finally, the modelling and DPD techniques are both evaluated using the experimental results of the GaAs PA.

Keywords

• gallium arsenide
• radiofrequency amplifiers
• linearisation techniques
• power amplifiers
• distortion
• iii-v semiconductors
• power amplifier predistortion
• rf power amplifiers
• saleh behavioural model
• saleh coefficients
• third-order intercept point
• solid-state pa technology
• manufacturing specifications
• memoryless amplitude-to-amplitude nonlinearity
• linearisation method
• digital predistortion
• am-am nonlinear distortion
• dpd techniques
• gaas