Thesis defense of Tristan LECOCQ - December 22th, 2023

Tristan LECOCQ will defend his thesis on December 22th, 2023 at 10:00 a.m., (amphi JP. DOM – IMS Laboratory) on the subject : “Design of power amplifiers in 130nm CMOS SOI and 28nm FD SOI technology for 5G NB-IoT applications”.

The development of 5G opens up new possibilities for applications related to the Internet of Things. With the objective of increasing the density of connected objects, the development of new communication protocols is necessary. This new standard, NB-IoT, requires the design of low-cost transceivers for large-scale deployment. The use of CMOS SOI technologies is ideal for such an application, as they offer higher performance than CMOS technologies at a similar cost. However, the design of PAs in SOI CMOS technology remains a challenge due to the high output power required. In addition, IoT applications require the design of high-efficiency PAs, which degrade amplifier linearity. Finally, as the NB-IoT bands are spread over the entire sub-6 GHz frequency spectrum, a broadband amplifier is preferable.
To address these constraints, the thesis work focuses on the design of high-power, high-efficiency PAs in CMOS SOI technology with a broadband approach. Two technologies are investigated, 28nm FDSOI and 130nm PDSOI, in order to identify the strengths and limitations of each for NB-IoT applications. Four power amplifiers and one co-integrated circuit are presented in the scope of the manuscript. First, two 28nm FDSOI amplifiers are detailed, including a PA Doherty based on hybrid couplers on capacitive load with OCP1 enhancement by reconfigurable adaptive bias. Next, a pseudo-differential power amplifier with broadband transformers is presented, followed by an ultra-broadband (50 MHz – 2.3 GHz) active-balun amplifier in 130nm PDSOI. Finally, the co-integration of the pseudo-differential PA with an antenna switch and the feasibility study of such a circuit for an NB-IoT application are discussed.