On Monday 8 October, PhD student Michele Squartecchia from DTU Electrical Engineering succesfully defended his PhD on InP DHBT MMIC Power Amplifiers for Millimeter-Wave Applications.
Examiners at the defence were Full Professor Paolo Colantonio, University of Rome Tor Vergata, Italiy, Senior Researcher, Ph.D. Mingquan Bao, Ericsson AB, Sweden, and Associate Professor Jørgen Dall from DTU Space.
Michele's PhD project has focus on the progress in semiconductor device technology, in particular compound semiconductor transistors such as High Electron Mobility Transistor (HEMT) and Heterojunction Bipolar Transistor (HBT) devices, enables the development of wireless communication circuits operating at frequencies around 100 GHz and above. At such high frequencies, monolithic microwave integrated circuit (MMIC) technology becomes mandatory. The main bottleneck in mm-wave systems today is the power
amplifier (PA). The high operating frequency of semiconductor devices, in particular silicon based, has been obtained by aggressive geometrical downscaling. As a consequence, the available output power per semiconductor device is limited due to the reduced breakdown voltages.
Compared with other semiconductors, InP DHBT technology offers a combination of very high frequency of operation and high voltage signal swing together with the potential for high density of integration. These are all recognized advantages for the implementation of mm-wave MMICs with high output power capability as required by emerging mm-wave systems.
In this project, suitable circuit topologies for mm-wave PAs have been investigated based on currently available device models. Several implementations of PA MMICs targeting emerging applications at E-band have been realized and measured at III-V Lab, a joint research laboratory of Nokia Bell Labs, Thales, and CEA-Leti located in Palaiseau (France). The designed MMIC represent a significant contribution for further development of modern mm-wave applications. On-chip tests revealed promising results for wireless communications and radar appliances.