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- Author
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Ilić, Milan, Đorđević, Antonije, Budimir, Đurađ, Nešković, Nataša, Saranovac, Lazar, Bukvić, Branko M., Ilić, Milan, Đorđević, Antonije, Budimir, Đurađ, Nešković, Nataša, Saranovac, Lazar, and Bukvić, Branko M.
- Abstract
This dissertation addresses the improvement of telecommunication systems. The proposed solutions can be implemented in both present and future telecommunication systems. After a brief introduction regarding the classes of amplifiers operating at microwave frequencies, three power amplifiers are presented. All three amplifiers are designed for modern telecommunication systems. More precisely, they are able to operate in several frequency bands. In the process of the amplifier design, the focus was set on the amplifier efficiency. Hence, the first two amplifiers are designed and fabricated to operate in class AB. In the first, reconfigurable amplifier, one of two possible operating frequencies can be chosen by switching on or off a PIN diode in the input matching network. The second, tunable, amplifier is designed and fabricated in such a way that the operating frequency can be continuously changed, between the lower and upper frequency boundaries. This is achieved by controlling the bias of the varicap diode, positioned in the input matching network. The third amplifier is designed and fabricated to operate in class J. Firstly, a novel theory describing the operation and design procedure of a class-J power amplifier is presented as an extension of the existing theory given in the literature. In the process, novel simple formulas are derived which govern the amplifier efficiency. An amplifier in class J is designed and fabricated following the proposed theory. Results obtained by numerical simulations and measurements on fabricated prototypes are in excellent agreement, thus verifying the proposed theory. Finally, simulation results are presented that characterize the amplifier performance when it is excited by some of the wideband signals used in modern telecommunication systems. The obtained results, which give insight in the linearity of the designed amplifier, are comparable with other results published in the literature, thus they additionally validate the applic
- Published
- 2017