Aras, Yunus Erdem2020-02-272020-02-272020-022020-022020-02-26http://hdl.handle.net/11693/53503Cataloged from PDF version of article.Thesis (Master's): Bilkent University, Department of Electrical and Electronics Engineering, İhsan Doğramacı Bilkent University, 2020.Includes bibliographical references (leaves 43-46).RF power amplifiers (PA) with high efficiency and linearity are in high demand for modern communication systems. Modulated signals having a high peakto-average power ratio (PAPR) require PA’s to maintain these features in the output-back-off (OBO) region. Since higher linearity always brings the trade-off in the form of lower efficiency, a PA having both high efficiency and linearity is challenging requirement for RF designers. Load modulation is one of the promising techniques offering good efficiencylinearity trade-off under OBO conditions for conventional PAs. This work presents an analytical model for the load modulated balanced amplifier (LMBA) using the recently introduced analytical non-linear model of a RF power transistor. We show that it is possible to predict the efficiency and nonlinearity of the LMBA reasonably well using this simple transistor model having only a small number of parameters. To test the performance of the analytical model, we designed an LMBA using three identical discrete RF transistors and 3-dB hybrid couplers. The model parameters of the 5-W GaAs PHEMT are determined from the I-V characteristics and load-pull measurements. LMBA works at 1.7 GHz with a peak output power of 37.5 dBm and with a peak efficiency of 53%. The efficiency is measured to be 47% at 6 dB output-back-off.xii, 50 leaves : charts (some color) ; 30 cm.Englishinfo:eu-repo/semantics/openAccessLoad modulationHarmonic modelBalanced amplifierHigh-efficient power amplifierBack-off efficiencyThesisB155761