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A.R. Qureshi

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3 records found

Journal article (2018) - Abdul Raheem Qureshi, Mustafa Acar, Sergio C. Pires, Leonardus Cornelis Nicolaas de Vreede
Packaged integrated low-pass quasi-load insensitive (QLI) class-E matching is proposed for the realization of energy-efficient wideband Doherty and outphasing transmitters. In view of this, a dedicated QLI class-E harmonic matching technique, suitable for in-package integration has been developed, optimized, and evaluated. As proof of concept, very compact, as well as easy to assemble, dual-input load-modulating transmitters have been realized. In this paper, we focus on a QLI class-E matched wideband Doherty that provides 71% peak efficiency (± 3%) at 48-dBm saturated output power and 49% (± 7%) efficiency at 6-dB power backoff, over a 1200-MHz frequency span (1.4-2.6 GHz), yielding 60% fractional bandwidth (BW). When tested with single-carrier long-term evolution (LTE) signals, having a 7-dB peak-to-average ratio, average efficiency remains close to 49% (± 3%) for the entire 60% fractional BW. The realized demonstrator shows excellent linearizability with adjacent channel power ratio and normalized mean square error levels below -50 dBc and -36 dB, respectively, even when operated in simultaneous dual-band LTE operation. ...
Conference paper (2017) - Abdul Qureshi, Mustafa Acar, Sergio Pires, Leo de Vreede
Doherty and Mixed-mode outphasing RF power amplifiers (PAs) that make use of package integrated quasi-load insensitive (Pi-QLI) Class-E GaN transistors are presented. The package integrated harmonic terminations facilitate very simple and compact amplifier implementations. Using these proposed devices, a “Class-E” Doherty PA with 58.3% average efficiency and -49 dBc ACPR after linearization, as well as, a Mixed-mode “Class-E” outphasing PA with an average efficiency of 66.6% and -51.6 dBc ACPR, after linearization using a single carrier WCDMA, PAR=7dB at 2.14GHz, are presented. ...
Conference paper (2016) - A. R. Qureshi, M. Acar, J. Qureshi, R. Wesson, L. C. N. de Vreede
This paper presents a novel dual-input Doherty-Outphasing Power Amplifier (DOPA) architecture that combines the efficiency advantages of Doherty and Outphasing amplifiers in power back-off (PBO). The proposed architecture, utilizes Doherty operation from peak power to -6dB PBO and mixed-mode outphasing from -6 to -14 dB PBO. A 2.14 GHz 112W GaN DOPA has been designed to demonstrate the concept, it provides 66% peak efficiency and more than 50% efficiency over a 12 dB PBO range. ...