On Friday 22 February, PhD student Bruno Cimoli from DTU Electrical Engineering succesfully defended his PhD on Microwave Circuits for Advanced Modulation Formats and Broadband Communication Systems.
Examiners at the defence were Professor Giorgio Leuzzi, University of L'Aquila, Italy, Principal Engineer, Ph.D. Johan Jacob Mohr, Mellanox Technologies and Associate Professor Kaj Bjarne Jakobsen from DTU Elektro.
Bruno's PhD project has focus on the future demand for faste internet connections requires a continuous development and improvement of telecommunications in terms of capacity, number of users and coverage that networks can provide. For achieving such goals, a necessary step is developing and providing hardware that can handle them. This project investigates microwave hardware solutions for short-range (SR) communications over optical and wireless channels. More specifically, this research covered tow main scenarios: optical intra-data center and ultra-wideband (UWB) wireless communication systems.
The first part of this project deals with SR optical cables for datacenters, which are the facilities that store the majority of the data from the internet. SR cables usually employ adopt robust and simple baseband modulations, such as non-return-to-zero (NRZ) and pulse amplitude modulation (PAM). This project investigates the alternative partial response (PR) modulation formats, which can significantly boost the spectral efficiency, which is the number of bits per Hertz, of an NRZ or PAM signal. The simplest PR modulator scheme consists in applying an analog microwave low pass filter (LPF) to the signal. This project investigates how to optimize PR modulators based on analog microwave LPF and eventual alternatives.
The second part of this project investigates microwave components for ultra-wideband (UWB) wireless communication systems. More specifically, the target are envelope detectors (EDs), which are electronic components able to recover the data or envelope from an RF modulated signal. We proposed three ED designed in microstrip technology and able to operate in UWB systems. The first two detectors are based on Schottky diodes, while the third on high electron mobility transistors. Experimental results of the three detectors showed outstanding results in terms of fractional bandwidth, which describes the frequency band occupied by the transmitted data in proportion to the frequency band where the device is operating.