Adrián Llop Recha defended his PhD thesis

The defense location was SmallTalk auditorium, Ole Johan Dahls hus, UiO.

Main research findings
Microwave-based sensors are gaining attention in medical research, particularly for use in wearable health devices. These sensors interact with the body in a non-invasive manner and have been explored for applications such as imaging, monitoring vital signs, and measuring blood sugar levels. However, transcutaneous biomarker analysis using microwaves remains challenging due to the complexity of human tissues, which can reduce measurement reliability. Improving the accuracy of these sensors is essential for making them a viable alternative to more invasive medical tests.

In this work, we present a technique based on coaxial probes that improves the estimation of the dielectric properties of subcutaneous tissue from superficial measurements on bi-layered samples through computational and experimental studies.

To implement this technique outside the laboratory, miniaturization of the bulky instrumentation is required. To that end, we propose an integrated frontend design. For efficient optimization of the circuit parameters, a machine learning-based design tool was developed and shown to yield good results. Finally, we discuss the use of heart rate in blood spectroscopy. A wideband sensor for pulse monitoring is introduced. Subsequent experiments with commercial diabetic tests highlight the need for better stabilization methods and further clinical research into the dielectric properties of blood glucose.

Prior to the defense, at 11:15 on the same day, Adrián presented his trial lecture "Medical applications of microwaves within and outside the hospital".

Adjudication committee

• Professor Dominique Schreurs, KU Leuven, Belgium
• Chief Scientist Kjetil Folgerø, Norwegian Research Centre AS, Norway
• Professor Sven Peter Näsholm, University of Oslo, Norway

Supervisors

• Associate Professor Kristian Gjertsen Kjelgård, Department of Informatics, University of Oslo, Norway
• Professor Dag Trygve Eckhoff Wisland, Department of Informatics, University of Oslo, Norway
• Professor Gert Cauwenberghs, University of California, San Diego, USA
• Professor Emeritus Tor Sverre Lande, Department of Informatics, University of Oslo, Norway

Read more at the UiO Department of Informatics webpage.