PhD Defense of HO Anh Tu

Abstract:
The substrate integrated waveguide (SIW) technology has been known at the end of the twentieth century, drawing interest from researchers and industry due to their low loss, high power handling, electromagnetic immunity and low-cost manufacturing. However, their large dimension is considered as a major drawback for their integration into a RF system below 15 GHz. To offer a high miniaturization, the slow-wave SIW (SW-SIW) technology was proposed in 2014. Hence, during this research, a novel SIW cavity-backed antenna using the slow-wave concept (SW-CBSA) was investigated, leading to a miniaturization of 47%, and a gain of 5 dBic. Two 1x4 antenna arrays were also carried out, a first one using a slow-wave microstrip-based feeding network and a second one using a SW-SIW-based one to improve electromagnetic shielding. Both antenna arrays offer good performance (with a measured gain of 10.8 dBi), and a strong size reduction (about 65%) as compared to the classical SIW-based antenna array counterpart. Then, passive microwave sensors for humidity detection were developed by combining the SW and air-filled (AF) SIW technologies. Thus, a PAF-SW-SIW resonator and a quarter-mode PAF-SW-SIW antenna were realized, leading to a surface miniaturization of 74% and 93%, respectively, as compared to AF-SIW. For the quarter-mode PAF-SW-SIW antenna, a measured sensitivity of 283 kHz/RH% was obtained. The two proposed research topics developed in this PhD thesis allow demonstrating the interest of slow-wave topology for size reduction while keeping interesting performance.

Jury members:
• Emmanuel PISTONO -  Supervisor
• Philippe FERRARI - CoSupervisor
• Dominique BAILLARGEAT - Examiner
• Anne-Laure PERRIER - Examiner
• Didier VINCENT - Reviewer
• Fabien FERRERO - Reviewer