The project group on Power Amplification implements a specific expertise on the non-linear modelling of power transistors and the development of new design methods and novel architectures for non-linear circuits. Our research activity is focused on new transistor technologies such as Gallium Nitride (GaN).
In the context of European scientific collaborations, the project team develops new non-linear electrothermal models dedicated to power process on emerging technologies such as GaN. All these modelling activities are of prime importance during the follow-up of each technological improvement in the face of thermal management and trapping effects involved in such emerging power technology.
PHEMT GaN 12x75µm
Advanced methods of pulsed I-V and pulsed S-parameters measurements have been developed at the laboratory so that to analyse in depth the thermal and trapping effects involved in high power devices.All these measurement tools are always evolving to adapt to the new challenges involved in the characterization of new power technologies (GaN) whose power densities are ten times higher than those of conventional power technologies (GaAs).
Distributed cascode GaN HEMT
The expertise on the non linear modelling during the follow-up of technological process enable to efficiently implement the design of demonstrators using the latest technological processes. Here is illustrated the design of a wide band 4-18GHz distributed power amplifier using optimised cascode GaN HEMT active cells flip-chip onto an AlN substrate integrating the passive matching elements.
The project group on Power Amplification implements a specific expertise on the design methods of wide band power amplifiers. New optimuOptimum distributed power architectures are based on optimised profile of input and output artificial lines and the integration of different size of active components (non uniform DPA) or pre-matched cascode cells depending on the required bandwidth. Here is illustrated the concept of non-uniform distributed power amplifier designed on GaAs technology.m architectures have been developed in the case of moderate and wide frequency bands.
Non-uniform distributed PA 1W, 4-18 GHz
Optimum distributed power architectures are based on optimised profile of input and output artificial lines and the integration of different size of active components (non uniform DPA) or pre-matched cascode cells depending on the required bandwidth. Here is illustrated the concept of non-uniform distributed power amplifier designed on GaAs technology.
Our expertise on distributed power amplifiers leads us to develop specific architectures dedicated to the interface between microwave and optical signals involved in high data rate optical communications. Specific demonstrators have been developed such as 40GHz driver for Electro Absorption Modulator and also a DC-40GHz transimpedance distributed amplifier for 40Gb/s communications.
One of the main breakthrough in power amplification required by the next generation of communications systems is to maintain high performances of power added efficiency and linearity for complex modulations presenting very large PAR (Peak-to-Average-Ratio). Our project team is involved in different kind of solutions such as Doherty architectures, adaptive bias and envelope tracking for complex modulations.
16 QAM with/without a dynamic bias control
Here is presented an example of power amplifier operating at 20GHz, which integrates a new concept of dynamic bias control in the case of 16QAM modulation leading to significant improvement of efficiency and EVM.
40 GHz Balanced sub-harmonic mixer using cold HEMTs
Our research experience on non-linear modelling and power amplifiers design leads us to conduct researches on new architectures and new design methods of specific non-linear circuits such as multipliers and mixers. Here is presented a new architecture of 40GHz balanced sub-harmonic mixer, which has been integrated on GaAs technology using cold HEMTs.