Date of Submission

5-2023

Document Type

Thesis

Degree Name

Master of Science in Electrical Engineering

Department

Electrical & Computer Engineering and Computer Science

Advisor

Mohsen, Sarraf, Ph.D.

Committee Member

Vahid Behzadan, Ph.D.

Committee Member

Ali Golbazi, Ph.D.

Committee Member

Moin, Bhuiyan, Ph.D.

Keywords

Radio-Frequency Power Amplifier, Digital Predistortion, Power Amplifier Linearization Techniques, FIR (Finite Impulse Response) Filter, LMS (Least Mean Squares) Algorithm

LCSH

Amplifiers, Radio frequency, Adaptive filters, Algorithms

Abstract

Radio Frequency (RF) Power Amplifiers (PA) are fundamentally non-linear due to their design and environmental effects, this non-linearity reduces performance and introduces distortion to the system. To improve the linear region of operation an adaptive Digital Predistortion Process (DPD) is used consisting of an adaptive Finite Impulse Response (FIR) filter utilizing the Least Means Square (LMS) algorithm. Unlike other DPD processes this one is adaptive in nature and requires no calibration allowing the digital pre-distorter to keep up with the dynamic changes in the PA non-linearity. The performance of this process is evaluated on the ability to increase the linearity of the PA thus decreasing distortion. The increase in linearity reduces the gain of harmonic frequencies and sidelobe intermodulation frequencies of the inputs. The performance is derived through multiple simulations in MATLAB which evaluate the effectiveness of the algorithm and the optimized design parameters. The results indicate that the adaptive algorithm is a viable method for reducing distortion and increasing the linear region of a PA. Due to these improvements this method would be a useful aid in RF system design and provides an economic advantage in high volume designs that require RF P As.

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