Electrothermal design and realization of high efficiency class F power amplifier

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Metadata	Details
Publication Date	2018-08-27
Journal	Espace École de technologie supérieure (École de technologie supérieure)
Authors	Mustafa Elarbi

Abstract

With the increasing widespread use and popularity of cell phones, laptops and similar electronic mobile equipment, there is a subsequent rising need for faster operational speeds. At the same time, increasing amounts of energy are both being used and demanded. How to satisfy these growing needs through longer battery life is currently a major focus of research.\n\nPower amplifiers (PAs) on wireless devices are causing endless problems for users of wireless telecommunication equipment due to their drain on the power system. Researchers are also looking into ways to increase the operational power-added efficiency (PAE) in amplifiers, this leads to reduce quantity of dissipated power. PAE changes DC power into RF, so when PAE is amplified, wireless devices can draw the same level of energy even while consuming less. Of particular interest to researchers are the non-linear class-F and class F invers PAs, which have a deserved reputation for their high levels of energy output and exceptional PAE. Class-F enhances PAE through the control of harmonic content.\n\nAgilent’s Advanced design system (ADS) can be applied in the performance of simulations and desing work. Cree’s compagny provided the ADS model of Cree’s CGHV1J006D high elcton mobility transistor (HEMT). A high efficiency PA was built using LTCC technology on an Ferro A6M. Both the input and output harmonics are controlled, while the input wave-shaping network dictates the shape of waveforms at the gate. Furthermore, in stopping harmonics using suitable terminators positioned at the output, we get a square voltage waveform and a half-sine current waveform near the transistor drain terminal. The spaces shared by the current waveforms and the voltage can also be reduced in size, as can the energy use of the active device.\n\nThe outcome was the ability to run a device at 5.7GHz on a PAE of 54.63%, and 36.25dBm output power. In addition, a novel thermal reliability analysis method based on ANSYS is proposed also to evaluate PA thermal characteristic. We used some materials have high thermal conductivity like a Cupper Diamond to dissipate the heat to the ambient.\n\nThis work demonstrates Class-F PA’s ability to radically improve PAE by stopping the second and third harmonic powers delivering to the load and by having the waveforms shaped near the transistor terminals.

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