24 Mai – Thesis defense - Thomas Capelli

10 h30 Amphi Jean-Paul Dom - laboratory IMS / building A31 (University of Bordeaux - Talence campus)

Power amplifiers for 5G phased arrays in ST CMOS065SOIMMW technology.

Mobile telecommunications, in order to support its insatiable needs, has been finding ways to improve its capabilities for over thirty years now. In 2019 the fifth generation (5G) is on trial to ensure connection not only to the ever-growing cell phone market, but also to the vast world of the Internet of Things (IoT). In order to meet its goals, 5G marks an unprecedented expansion in the frequency bands used. Indeed, bands up to 60 GHz and beyond are part of the network's ambitions and this implies radical technological changes that impact all dedicated electronics. New higher frequencies, higher propagation losses in the air, and higher requirements, antenna phased arrays are introduced to overcome all these constraints and impose a completely new system architecture and interface for the RF front-end of mobile communications.
In this work, we propose an analysis of these phased antenna arrays and the constraints they represent particularly for power amplifiers (PA), such as the parasitic load variation and the behavior of the components generated by the non-linear behavior of the latter. An evaluation of the active load variation due to the different coupling existing in the antenna networks is proposed as well as its impact on the performance of the amplifiers, particularly in terms of power added efficiency (PAE). The behavior of nonlinearities such as third-order intermodulation products (IMD3) is shown in antenna arrays. A concept using the principle of beam generation and steering of antenna arrays is proposed, allowing for relaxing the linearity constraints of 5G amplifiers and thus allowing a reduction of their power consumption. An implementation of an AP using this principle is demonstrated in ST CMOS 65 nm PD-SOI technology at 28 GHz

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