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PEOPLE@HES-SO – Directory and Skills inventory

PEOPLE@HES-SO
Directory and Skills inventory

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Boegli Alexis

Boegli Alexis

Professeur-e HES associé-e

Main skills

Systèmes embarqués

Technologies radiofréquence (RF)

Bluetooth Low Energy (BLE)

Localisation RF

Électronique analogique

Projets de recherche appliquée

Transfert de technologie

  • Contact

  • Teaching

  • Publications

  • Conferences

  • Portfolio

Main contract

Professeur-e HES associé-e

Haute Ecole Arc - Ingénierie
Espace de l'Europe 11, 2000 Neuchâtel, CH
DING
BSC HES-SO en Informatique et systèmes de communication - Haute Ecole Arc - Ingénierie
  • Électrotechnique - Électronique - Technologie RF
Microengineering - EPFL
  • Electrotechnics I (remplassant du prof. Yves Perriard)

2023

Indoor Real-time Localization System for Internet of Things Application
Doctoral thesis
Doctoral thesis defended by Pooneh Mohaghegh and co-supervised by Alexis Boegli

Boegli Alexis

2023,  Lausanne : EPFL.  184  p.

Yves Perriard, Alexis Boegli

Link to the publication

Summary:

Dielectric localization systems offer promising solutions for the indoor positioning of objects and people in smart environments. Traditional approaches often suffer from limited accuracy, high energy consumption, or complex infrastructure requirements, limiting their deployment in real-world applications. In this context, Bluetooth Low Energy (BLE) has emerged as a viable option for real-time localization in Internet of Things (IoT) applications, offering a good compromise between cost, energy efficiency, and availability.

This thesis explores the design, development, and validation of an indoor localization system using BLE technology, with a focus on real-time tracking, multi-device scalability, and signal processing optimization. A key aspect of the work is the implementation of angle-of-arrival (AoA)-based localization, using off-the-shelf BLE antennas and receivers. The system architecture, signal processing pipeline, and performance evaluation metrics are discussed in detail.

Several experiments are conducted in realistic indoor environments to assess localization accuracy, responsiveness, and robustness under varying conditions. Results demonstrate the feasibility of achieving sub-meter accuracy in real time, making this solution attractive for applications such as asset tracking, smart buildings, and industrial monitoring. The outcomes of this work lay the foundation for further development of distributed, energy-efficient, and scalable indoor positioning systems for IoT.

2022

Ultra-high voltage, low power and energy recovering electronics for dielectric elastomer actuators
Doctoral thesis
Doctoral thesis defended by Raphel Mottet and co-supervised by Alexis Boegli

Boegli Alexis

2022,  Lausanne : EPFL.  136  p.

Yves Perriard, Alexis Boegli

Link to the publication

Summary:

Dielectric elastomer actuators (DEAs) are a class of electroactive polymers capable of mimicking biological muscles. They offer large strains, high energy densities, and fast response times, making them suitable for a wide range of applications including robotics, haptics, and biomedical devices. However, their implementation is hindered by the requirement of high driving voltages (in the kV range), limited energy efficiency, and the lack of integrated compact and efficient driving electronics.
This thesis addresses these challenges by exploring the design and implementation of ultra-high voltage, low power, and energy-recovering electronics dedicated to DEAs. A strong focus is placed on system-level integration and practical implementations to pave the way for real-life applications.
Multiple converter architectures and control strategies are investigated and validated through simulations and experimental prototypes. Results demonstrate the feasibility of compact DEA drivers that significantly reduce power consumption while recovering energy during actuator discharge, marking a key step toward autonomous and efficient DEA systems.

2021

Bluetooth Low Energy Direction Finding Principle
Scientific paper

Pooneh Mohaghegh, Boegli Alexis, Yves Perriard

IEEE Internet of Things Journal, 2021 , vol.  9, no  3, pp.  2236-2248

Link to the publication

Summary:

This article presents the principles of Bluetooth Low Energy Direction Finding (BLE-DF) as introduced in Bluetooth 5.1. It describes the theoretical basis for Angle of Arrival (AoA) and Angle of Departure (AoD) estimation using antenna arrays, as well as the IQ sampling process and signal formatting defined in the standard. The work includes practical implementation insights, hardware requirements, and performance evaluation, serving as a foundation for the development of BLE-based indoor localization systems.

Ultra-High-Voltage (7-kV) Bidirectional Flyback Converter Used to Drive Capacitive Actuators
Scientific paper

Raphaël Mottet, Moisés Almanza, Lucie Pniak, Boegli Alexis, Yves Perriard

IEEE Transactions on Industrial Electronics, 2021 , vol.  69, no  4, pp.  3565-3575

Link to the publication

Summary:

This article presents the design and experimental validation of a 7-kV bidirectional flyback converter intended for driving capacitive actuators, such as dielectric elastomer actuators (DEAs). The converter combines ultra-high-voltage operation with a compact form factor and high energy efficiency. Both charging and discharging phases are handled by the same power stage, with accurate voltage control and low switching losses. Experimental results demonstrate the suitability of the converter for low-duty-cycle, high-voltage actuator applications.

Schmitt Trigger-Based Control Strategy for the Discharge Phase of an Ultra-High-Voltage Bidirectional Flyback
Scientific paper

Raphaël Mottet, Boegli Alexis, Yves Perriard

IEEE Transactions on Power Electronics, 2021 , vol.  37, no  5

Link to the publication

Summary:

This article presents a Schmitt trigger-based control strategy for safely discharging an ultra-high-voltage bidirectional flyback converter used in dielectric elastomer actuator (DEA) applications. The proposed solution ensures accurate voltage control without complex feedback regulation, reducing losses and improving robustness. Experimental validation demonstrates the circuit's ability to operate in real time with high reliability across a wide range of output voltages.

2020

Investigating Optimal Settings for Distance Calculation with a Low Frequency Low-Power RF System
Scientific paper

Pooneh Mohaghegh, Dardan Privca, Boegli Alexis, Yves Perriard

IEEE Sensors Journal, 2020 , vol.  21, no  6, pp.  7399-7408

Link to the publication

Summary:

This paper investigates the impact of different system parameters on the accuracy of distance estimation in a low-frequency, low-power RF localization system. Operating at 125 kHz, the system uses RSSI-based measurements for positioning. The study evaluates sampling rates, antenna configurations, and calibration techniques to identify optimal conditions for indoor deployment. Experimental results validate the system’s robustness and low energy footprint for precise, real-time localization.

2017

An Energy Efficient Power Converter for Zero Power Wearable Devices
Doctoral thesis
Doctoral thesis defended by Milad Ataei and co-supervised by Alexis Boegli

Boegli Alexis

2017,  Lausanne : EPFL.  163  p.

Pierre André Farine, Alexis Boegli

Link to the publication

Summary:

This doctoral addresses the design and implementation of energy-efficient power converters aimed at wearable devices with extreme constraints on power consumption and autonomy. The proposed system focuses on "zero power" operation, targeting applications that rely on energy harvesting to extend device lifetime or eliminate the need for batteries altogether.

The work presents converter architectures designed to operate reliably at very low power levels, integrating strategies for energy recovery, ultra-low leakage, and adaptive control. The converters were validated through both simulation and prototyping, demonstrating their suitability for biomedical monitoring and other low-power wearable systems.

2016

Phase and Frequency Self-Configurable Efficient Low Voltage Harvester for Zero Power Wearable Devices
Scientific paper

Milad Ataei, Boegli Alexis, Pierre-André Farine

IEEE Transactions on Circuits and Systems I: Regular Papers, 2016 , vol.  63, no  11, pp.  2010-2021

Link to the publication

Summary:

This paper presents an energy harvesting circuit tailored for wearable applications, capable of operating from extremely low input voltages. The proposed architecture is self-configurable in both phase and frequency domains and achieves high energy efficiency with voltages as low as 30 mV. The system is based on a voltage doubler topology and integrates intelligent pulse generation to optimize startup and steady-state performance. Experimental results validate the circuit’s suitability for powering zero-power wearable devices such as EEG/ECG electrodes using thermoelectric generators (TEGs).

2015

Silicon Micromachined Ultrasonic Scalpel for the Dissection and Coagulation of Tissue
Scientific paper

Boegli Alexis

Biomedical Microdevices, 2015 , vol.  17, no  77

Link to the publication

Summary:

This article presents the design, modeling, fabrication, and experimental validation of a planar ultrasonic scalpel based on a micromachined silicon acoustic horn. The use of silicon offers benefits in weight, thermal conductivity, and manufacturability compared to conventional titanium-based tools. The scalpel integrates piezoelectric actuators in d31 mode and operates in resonance to produce longitudinal oscillations suitable for tissue dissection and coagulation. Finite element modeling and laboratory testing, including cutting tests on biological tissues, demonstrated the performance, robustness, and thermal behavior of various designs. The results confirm the feasibility of cost-effective silicon-based ultrasonic scalpels for high-precision surgical applications.

Design of an Integrated Thermoelectric Generator Power Converter for Ultra-Low Power and Low Voltage Body Energy Harvesters Aimed at ExG Active Electrodes
Scientific paper

Milad Ataei, Christian Robert, Boegli Alexis, Pierre-André Farine

Journal of Micromechanics and Microengineering, 2015 , vol.  25, no  10

Link to the publication

Summary:

This paper describes a detailed design procedure for an efficient thermal body energy harvesting integrated power converter. The procedure is based on the examination of power loss and power transfer in a converter for a self-powered medical device. The efficiency limit for the system is derived and the converter is optimized for the worst-case scenario. All optimum system parameters are calculated respecting the transducer constraints and the application form factor. Circuit blocks including pulse generators are implemented based on the system specifications and optimized converter working frequency. At this working condition, it has been demonstrated that the wide area capacitor of the voltage doubler, which provides high voltage switch gating, can be eliminated at the expense of wider switches. With this method, measurements show that 54% efficiency is achieved for just a 20 mV transducer output voltage and 30% of the chip area is saved. The entire electronic board can fit in one EEG or ECG electrode, and the electronic system can convert the electrode to an active electrode.

2013

Design and Energy Management Optimizations for Wireless Sensor Networks
Doctoral thesis
Doctoral thesis defended by Mitko Tanevski and co-supervised by Alexis Boegli

Boegli Alexis

2013,  Lausanne : EPFL.  220  p.

Pierre André Farine, Alexis Boegli

Link to the publication

Summary:

This doctoral thesis, defended by Mitko Tanevski at EPFL in 2013, addresses the design and energy optimization of wireless sensor networks (WSNs) for long-lifetime, low-power applications. The work focuses on architectural and circuit-level strategies to extend the autonomy of battery-powered sensor nodes through optimized energy management and communication protocols.

The thesis presents a complete system-level approach, including the design of low-power analog front-ends, adaptive wake-up strategies, power-aware digital architectures optimization. The solutions developed enable significant energy savings, improving the lifetime and reliability of autonomous sensing platforms for industrial and environmental monitoring.

2001

Model-Based Design Methodology for Microsystems
Doctoral thesis
Méthodologie de la conception de microsystèmes par la modélisation

Boegli Alexis

2001,  Neuchâtel : Université de Neuchâtel.  196  p.

Fausto Pellandini

Summary:

This thesis presents a top-down methodology for the design of microsystems, called the MicroSIM approach. Microsystems are complex, heterogeneous systems combining microstructures and electronics, often with strong coupling between components. The proposed method is based on behavioral modeling and relies on computer-aided design (CAD) environments. It allows early validation through simulation, helps manage interdisciplinary complexity, and facilitates the development of reusable design kits. Several examples illustrate how this approach enables better control over microsystem design from specifications to prototyping.

2025

Inversing the actuation cycle of dielectric elastomer actuators for a facial prosthesis
Conference

Stefania Konstantinidi, Quentin De Menech, Thomas Martinez, Paolo Germano, Boegli Alexis, Yoan Civet, Yves Perriard

SPIE Conference on Smart Structures/NDE (Electroactive Polymer Actuators and Devices XXVI), 04.03.2025 - 07.03.2025, Long Beach, Californie, USA

Link to the conference

Summary:

This work explores an inverted actuation strategy for dielectric elastomer actuators (DEAs) used in facial prostheses. Instead of being activated to contract, the DEA is constantly charged to maintain a stretched position and discharged to induce contraction. A discharge model was developed and validated experimentally. Results show that with a 2 Hz actuation frequency and 50% duty cycle, the discharge between cycles remains below 3%, reducing energy consumption by 1.5% per cycle compared to continuous actuation. The study offers promising insights for low-duty-cycle biomedical applications.

2022

New Design of Antenna Array for Bluetooth Direction Finding
Conference

Pooneh Mohaghegh, Boegli Alexis, Yves Perriard

IEEE International Symposium on Antennas and Propagation (APS/URSI 2022), 10.07.2022 - 15.07.2022, Denver, Colorado, USA

Link to the conference

Summary:

This paper presents a compact antenna array design optimized for Bluetooth 5.1 Direction Finding (BLE-DF). The geometry and arrangement are designed to minimize the impact of multipath and mutual coupling while remaining compatible with commercial BLE modules. Simulation and experimental validation demonstrate the array's effectiveness in enabling accurate angle-of-arrival (AoA) estimation using BLE-compatible chipsets.

2021

An Analytical Model for the Prediction of the Maximum Output Voltage Reachable with an Ultra-High Voltage Flyback Converter Driving Capacitive Actuators
Conference

Raphaël Mottet, Boegli Alexis, Yves Perriard

IEEE Energy Conversion Congress and Exposition (ECCE 2021), 10.10.2021 - 14.10.2021, Vancouver, Canada

Link to the conference

Summary:

This paper proposes an analytical model to predict the maximum output voltage that can be reached by a flyback converter used to charge capacitive actuators. The model accounts for transformer parasitic elements and component non-idealities. The converter architecture targets ultra-high voltage applications such as dielectric elastomer actuators. Experimental results validate the model's accuracy and provide useful design guidelines for flyback-based high-voltage drivers.

Depth camera and electromagnetic field localization system for IoT application
Conference ArODES

Pooneh Mohaghegh, Rabia Saeed, François Tièche, Alexis Boegli, Yves Perriard

Proceedings of ASSE'21: 2021 2nd Asia Service Science and Software Engineering Conference, 24-26 February 2021, Macau, Macao

Link to the conference

Summary:

This article demonstrates person localization using a hybrid system consisting of an electromagnetic positioning system and a depth camera to authorize access control. The ultimate aim of this system is to distinguish moving people in a defined area by tracking the RF device and the people. It focuses on the application and incorporation of the received data from these two systems. Both systems send data simultaneously which is stored in a Docker container for further analysis. The data is processed in real-time to track the movement of the targets. The centralized database monitoring grants secure access to the information. The motive for using this hybrid system lies in the ever-growing need for accurate position determination for indoor and complex environments. Track and tracing are especially important in access-control applications. The system has a great impact on real-life access-control applications in malls, shops, train stations, and generally everyplace where the access control requires monitoring. The non-blocking feature plus the accuracy can provide ease of use for the users. Moreover, employing a low-frequency tag system does not suffer from the multipath effect and non-line of sight problems that are inevitable for indoor applications. By extending the number of users for a larger area, this system can replace traditional security gates with a pleasant look and comfortable application.

2020

Control Strategy for the Discharge Phase of an Ultra-High Voltage (>7kV) Bi-Directional Flyback Converter Driving Capacitive Actuators
Conference

Raphaël Mottet, Boegli Alexis, Yves Perriard

IEEE Energy Conversion Congress and Exposition (ECCE 2020), 11.10.2020 - 15.11.2020, Online (originally planned in Detroit, USA)

Link to the conference

Summary:

This paper presents a control strategy to safely manage the discharge phase in an ultra-high-voltage (>7kV) bidirectional flyback converter designed for capacitive actuators. The proposed method relies on a Schmitt trigger-based approach that simplifies the implementation and reduces energy loss. Experimental validation confirms the effectiveness of the strategy in enhancing efficiency and control robustness.

Application of a Low Frequency, Low Power Radio Frequency Positioning System for Real-Time Indoor Positioning
Conference

Pooneh Mohaghegh, Dardan Privca, Juan S. Botero-Valencia, Boegli Alexis, Yves Perriard

IEEE International Conference on Indoor Positioning and Indoor Navigation (IPIN 2020), 05.10.2020 - 07.10.2020, Online (original location: Lloret de Mar, Spain)

Link to the conference

Summary:

This paper presents a low-frequency, low-power radio frequency positioning system designed for real-time indoor localization. The system operates at 125 kHz and enables centimeter-level accuracy using signal strength measurements and triangulation. It targets applications requiring high precision and minimal power consumption, such as logistics and asset tracking. Experimental results validate the system’s feasibility and accuracy in constrained environments.

2014

Thermoelectric Energy Harvesting for Energy Autonomous Active EEG Electrodes
Conference

Boegli Alexis

International Conference on Thermoelectrics (ICT 2014), 01.07.2014 - 03.07.2014, Nashville, Tennessee, USA

Summary:

This paper presents the design and evaluation of a thermoelectric energy harvesting system for powering energy-autonomous active EEG electrodes. The approach combines compact thermoelectric generators (TEGs), a low-voltage power converter, and power management strategies tailored for wearable biomedical applications. Experimental results demonstrate the feasibility of powering active electrodes exclusively through body heat, supporting continuous biosignal acquisition without batteries.

Achievements

2022

Verfahren und System zur Kontrolle von Besuchern in einem Zugangsbereich innerhalb eines Freizeitparks

 2022 ; Patent

Collaborateurs: Boegli Alexis

Link to the achievement

Development of an access control system based on Bluetooth Low Energy (BLE) positioning and video analysis, enabling the association of a location measured via BLE signals with a person visually identified by a camera in an entry zone. This technology allows for contactless identity verification and access authorization. The patent covers the simultaneous use of multiple Bluetooth beacons, an overhead camera, and an algorithm for matching the visual entity to the BLE-measured position.


The patent was filed by e-liberty services SA, with a Swiss priority (CH 00295/21) and extended to Austria under number AT524899A2, published on October 15, 2022.

2013

Method of Real-Time Regulation Compliance for Wireless Transmitters

 2013 ; Patent

Collaborateurs: Boegli Alexis

Link to the achievement

This international patent (PCT WO2013174928A9) describes a method and firmware module enabling wireless transmitters—particularly those used in sub-GHz wireless sensor networks—to comply in real-time with regulatory constraints such as duty cycle, transmission time, and off-time imposed by ETSI or FCC. The proposed system integrates into the MAC layer and uses a circular buffer to monitor transmission history and dynamically adjust behavior to avoid regulatory violations. The invention is highly relevant to low-power, autonomous sensor nodes operating in constrained ISM bands. 

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