Short Bio 

Prof. Johan Stiens received the MSc degree in Electro-Mechanical Engineering with major in Applied Physics and the Ph.D. degree with greatest honors at the faculty of Engineering Sciences from the Vrije Universiteit Brussel (VUB) in 1990 and 1996, respectively. Since 2011 he holds the academic position of Professor at VUB and since 2017 he is the head of department of the department of Electronics and Informatics (ETRO). He teaches several courses in four master specializations of the Engineering Science faculties of three universities: at VUB, at Université Libre de Bruxelles (ULB) and at Universiteit Gent (UGent). The courses cover a wide spectrum, ranging from Micro-, Nano-, Opto- and Bio(medical) Electronics, Bio-electromagnetism and Modelling of Physiological Systems.

"Contribution to a sustainable society with innovative research based on smart multi-modal sensing and stimulation systems."

He is the director of the Biomedical Engineering program at VUB and co-chairman of the inter-university program of biomedical engineering organized between UG and VUB, elected as a member of the NCBME, National Committee of Biomedical Engineering of Belgium, associated to the Royal Flemish Academy of Belgium for Sciences and Arts. He is the national representative of Belgium in the IFMBE, International Federation for Biological and Medical Engineering. He is a member of the Centre for Neuroscience C4N of VUB. He is a member of the Innovation Council of the University Hospital UZ-Brussels. He is a part-time sr. researcher at IMEC. He is associated to the Green Energy Park, where he is responsible for the following projects. Hospital of the future

He has a strong focus on valorization of R&D results. He owns 13 granted patents and 3 are pending. He followed a university course on “start-up your own business” at VUB-TTI and a business-to-business industrial marketing course @ KVIV. He has been acting as a consultant for several years for an American IP company and Belgian research institute. He is also the co-founder of two spin-off companies (see below, achievements).

Research Interests 

Wearable medical sensor technology

Out-of-clinic monitoring and diagnosis is gaining attention in many countries as a means of reducing hospitalisation costs. Many sensor modalities exist to yield information about the physiological status of the human body: heart rate (variability), blood pressure, respiration rate, stress, temperature, blood oxygen saturation, skin conductance, arterial compliance, micro-vascular flow, the electro-encephalogram, etc.

The drive of the group is to bring the laboratory solutions outside the lab. Essential in this strategy is the incorporation of motion and other artefact compensation multi-modal solutions based on photo-plethysmography based sensing. Particularly, different implementations are being explored to obtain robust physiological readings from experiments set outside the lab, in hospital environments and at home, where subjects can be monitored in an unobtrusive fashion without restricting their quality of life.

Smart electroceutical: novel stimulation paradigms

Pharmaceuticals are leading the medical market for decades due to the over concentration on the biochemical interactions in the body. However, from an electrical engineering point of view, the body is also a very intriguing, as it is a complex, connected and controlled electrical network. Electroceuticals will open the world of implanted electronic control functions for triggering various organs of the human body by the nervous system. It is estimated that electroceuticals will become a mainstay of medical treatment over the next two decades, benefiting up to 2 billion people who are suffering from chronic diseases. The research group will focus on novel electrical devices and the interaction mechanisms with the electrical network of organs. Last but not least, the full potential of electroceuticals can also be extended to the field of bio-electromagnetism. The research group studies the impact of EM waves on different levels: system level (e.g. mice), on cellular, with emphasis on the mitochondrial level and finally at the molecular levels, e.g. enzymatic reactions or even on the diffusion of molecules in water.

Dielectric Spectroscopy of materials in the GHz-THz range

The interaction of mm and THz waves with materials is described by the frequency dependent dielectric permittivity and magnetic permeability function. For material compounds the adequate mixing formula needs to be derived. For the quantitative analysis it is also of paramount importance that the temperature and humidity or the phase changes of the materials are taken into account.

The materials of our interest include: technology materials for realizing integrated and packaged electronic circuits and systems: semiconductors, dielectrics, rubbers, polymers, liquids, powders, granular materials, mixtures… The target industries can be very diverse: electronic, chemical, food, pharmacy, biotech, agriculture, construction, ….

  • Characterization of material properties using quasi-optical vector-based measurement techniques (S-parameters)
  • Development of powerful and robust hierarchical algorithms (combinations of direct and indirect techniques) to extract material properties of single and multi-layer structures
  • Evaluation of dielectric mixing models of compounds and mixtures
  • Characterization of material properties using the transient Radar Methodology

Besides classic materials also meta-materials are studied, which exhibit in a particular frequency range negative dielectric permittivity and/or negative magnetic permeability. These properties yield new design options for a wide set of applications in the mm-wave and THz frequency range. Our research activities include: modelling and design of single and multi-layer Left Handed Materials, including symmetric and asymmetric split ring resonators, derivation of equivalent circuits and investigations of ultra-sensitive thin film sensors for all kind of materials.

Mm-wave Imaging & Sensing in the GHz-THz range

Millimeter waves offer a good combination of resolution and penetration for the development of active mm wave imaging systems for non-destructive testing applications. Our research activities focus on various imaging modalities such as physical aperture imaging, conventional and transient radar imaging, synthetic aperture imaging, near-field imaging and compressed sensing and imaging.

The research activities encompass the design of imaging system architectures, image forming optics, fast scanning techniques, multi-parameter (frequency, angle, polarization, phase) illumination techniques.

Conventional optical imaging systems in the mm-wave and THz range (0.1 < λ < 10 mm) cannot resolve microscopic details as the resolution in the far field is limited by diffraction (Rayleigh criterion). Super resolution is however feasible by detection of scattered evanescent waves, which are only detectable in the direct neighbourhood of the object by putting a field scattering microprobe. We investigate the potential of a scanning scattering type near-field mm-wave imaging method based on the interaction between a very sharp probe tip and the object whereby the resolution is no longer determined by the wavelength but by the sharpness of the tip.

Achievements (Honors & Awards) 

Industrial Valorization project: GEAR (Groups of Expertise in Applied Research). This Gear program contributed inception of 6 spinoff projects. Since 2006 he is a co-promoter and since 2016, he has been the spokesman-promoter of the ETRO-wide IOF-GEAR project. The actual GEAR-project is in collaboration with INDI, bringing together about 150 researchers in the domain of Technologies for Health.

Together with Prof. Guy Nagels, promotors of the interdisciplinary Senior Research Fellowship in the domain of the e-BRAIN project (2019-2029). This project offers the long-term planning of more than 10 years in the wide field of the neuro-engineering and comprises the involvement of a multitude of research groups of various faculties (IR, GF, LK, ES, RC). The selected candidate Jeroen Van Schependom started with the execution of the mandate in the academic year 2019-2020.

He has been the (co)-promoter of 34 finalized and/or running PhD projects.

Setting up new laboratories, including funding of Measurement & Technology Fabrication infrastructure projects, in collaboration with multi-disciplinary teams:

He has been the (co)promoter of the following instrumentation projects

  • Multiple projects in the domain of GHz-THz instrumentation, leading to state-of-the-art portable and table-top VNA spanning the spectral range from MHz to 750 GHz range and sampling oscilloscopes operating up to 85 GHz.
  • Nano-fabrication technology:
    • High-aspect ratio Deep RIE-etching equipment,
    • E-beam lithography, in collaboration with UGENT
  • Mitochondrial respiration project: Seahorse flux analyzer for cellular real-time bio-energetics monitoring.
  • Medical Wearable Technology laboratory
  • PAST: A fully equipped CO2 laser lab, with several lasers up to 50 W. (Research stopped in 2016).

Establishing several joint collaborations in the field of GHz-THz and global health

  • GHz-THz collaboration : UKENT (UK), State University of Campinas (Campinas, Brazil), Northwest University (Xian, China), Shangai University (Changia, China), University of Electronic Science and Technology of China (Chengdu, China), IRE-RAS (Moscow, Russia),
  • Global health: universities and hospitals in the following countries: Tanzania, Rwanda, Congo DR, Morocco, Ethiopia, Cuba.

He is author of one book on Gallium nitride related semiconductor devices. S. Rabbaa, G. Shkerdin, J. Stiens, GaN-based Semiconductor Devices: Theoretical Study of the Electronic and Opto-Electronic Characterization, editor Lambert Academic Publishing, December 2014. ISBN: 978-3-659-55781-1

He is the author or more than 300 (including 165 ISI) international journal and conference papers.

He is also the co-founder of two spin-off companies:  EqcoLogic (2005-2013) dealing with equalizer chips, successfully sold to the US-company Microchip; M2wave (2014), dealing with millimeter wave sensor technology, since May 2015 successfully integrated in the Swiss based company Aquantis, where he was a Member of the Board of directors and CTO till September 2017, when he returned full time to VUB to become the head of Department of ETRO.

  • He has been elected as a member of the NCBME, National Committee of Biomedical Engineering of Belgium, associated to the Royal Flemish Academy of Belgium for Sciences and Arts.
  • He is the national representative of Belgium in the IFMBE, International Federation for Biological and Medical Engineering.
  • He is a member of the Centre for Neuroscience C4N of VUB.
  • He is a member of the Innovation Council of the University Hospital UZ-Brussels, UZ-B.
  • He is a part-time sr. researcher at IMEC.
  • He is associated to the Green Energy Park, GEP, where he is co-leading the following projects:  Medical-Technical hospital infrastructure laboratory and for the Living Lab Flanders project.
  • Modelling of Physiological Systems (6 credits, titular) – 3 BA IR
  • Measurements and Analysis of Biomedical Signals (5 credits, titular) – 3 BA IR
  • Bioelectronics (3 credits, titular) – PP MA BME
  • Nano-and Optoelectronic devices (5 credits, titular) – 2 MA EE
  • Internship in Biomedical Engineering (6 credits, titular) – 1/2 MA BME
  • Biomedical devices: Sensors, stimulators, Drug delivery Systems (4 credits, titular) – 1/2 MA BME
  • Biomedical Product Development (6 credits, co-titular) – 1/2 MA BME
  • Micro-and Nanotechnologies for medical device design and fabrication (5 credits, co-titular)- 1 MA BME
  • Wave Physics in Living Matter (6 credits, co-titular) – 1/2 MA BME – 1/2 MA PHYS-UG
  • Technologies and Applications of Microelectronics and Photonics (6 credits, co-titular) – 2MA ACS
  • Bio-electromagnetism (3 credits, co-titular) – 1/2 MA BME