| The work presented in this master thesis focuses on diodes predistortion linearization, particularly for the solid-state power amplifiers (SSPA). Background discussion on common linearization techniques available to the power amplifiers designer is presented. In addition, a discussion of traditional and modern methods of nonlinearity characterization is presented. This includes the use of two-tone analysis. The operation of the diode predistortion linearizers is discussed in detail.;The present master thesis will explain two different types of linearization circuits. The first linearizer is a circuit, which uses the diode connected in parallel and direct polarization. The second circuit has the Schottky diodes in connection head to tail. In the case of the first circuit, we began with a first order predistortion circuit, used for the linearization of the travelling waves amplifiers (TWTA). We develop a second-order predistortion circuit, which gives a characteristic with two inflection points.;The second linearization circuit is a development of an ancient circuit, which was designed for low frequencies. For the two circuits, prototypes were built starting from their simulated circuits. The theoretical results were compared with experimental measurements and two systems of linearization were used to validate these results. For the two circuits the results show an improvement concerning the third order and the fifth order intermodulation distortion. Two linearization circuits were also presented. Considerations regarding the design, the simulations, and the layout were presented. In conclusion, several recommendations are made for future research. (Abstract shortened by UMI.)... |
