“Signal Processing in the AI era” was the tagline of this year’s IEEE International Conference on Acoustics, Speech and Signal Processing, taking place in Rhodes, Greece.

In this context, Brent de Weerdt, Xiangyu Yang, Boris Joukovsky, Alex Stergiou and Nikos Deligiannis presented ETRO’s research during poster sessions and oral presentations, with novel ways to process and understand graph, video, and audio data. Nikos Deligiannis chaired a session on Graph Deep Learning, attended the IEEE T-IP Editorial Board Meeting, and had the opportunity to meet with collaborators from the VUB-Duke-Ugent-UCL joint lab.

Featured articles:

• De Weerdt, B. et al., “Designing Transformer Networks for Sparse Recovery of Sequential Data Using Deep Unfolding” (https://ieeexplore.ieee.org/abstract/document/10094712)
• Yang X. et al., “Relevance Propagation through Deep Conditional Random Fields” (https://ieeexplore.ieee.org/abstract/document/10095075)
• Stergiou A. et al., “Play it back: Iterative attention for audio recognition” (https://ieeexplore.ieee.org/abstract/document/10096532, developed at the University of Bristol)

The ETRO team, comprising Salar Tayebi, Ashkan Zarghami, Manu Malbrain, and Johan Stiens, has developed an innovative programmable abdominal phantom. This device is designed to simulate various scenarios and pathologies related to ICU patients. Recently showcased at the 13th International Fluid Academy Days in Antwerp, it marks a significant step forward in the realm of medical training and research. This abdominal phantom is primarily aimed at enhancing the training experience for nurses and engineering students, providing them with a more hands-on and realistic learning environment. Additionally, it holds potential for use in validating medical equipment and facilitating research and development in medical technologies. Its introduction to the medical doctors’ ecosystem underscores its relevance and utility in contemporary medical education and practice

Guest vouchers for the VUB(next) wifi network should be asked 24 hours in advance at the service desk of VUB (SNOW). The request form can be found at https://vub.service-now.com.

In case of emergency (you forgot to request the vouchers) you can
– call VUB ICT Service Desk +32 (0) 2 629 37 37 or
– render them a visit PL9 5^th floor.
With some luck they will make the needed vouchers instantly.

You van visit the LEGO urban planner again and design your climate-resilient city at “Dag van de Wetenschap” (Science Day) on Sunday 26 November at Muntpunt.

The I Love Science Festival at Tour & Taxis in Brussels on October 13-15 was a great success, drawing over 150000 science and technology enthusiasts of all ages. ETRO.RDI enchanted attendees with interactive exhibits, including light-based physiological readings, acoustic camera art, a crypto escape room challenge, and an AI-driven urban climate model.

For those who missed out on this year’s event, mark your calendars for the next I Love Science Festival, and be sure to check out ETRO.RDI’s booths.

On October 6th 2023 at 17.00, Rana ElKashlan will defend her PhD entitled “GAN-ON-SI TECHNOLOGY FOR MODERN WIRELESS COMMUNICATION SYSTEMS: OPTIMISATION INSIGHT USING RF CHARACTERISATION”.

Everybody is invited to attend the presentation at the Room D.2.01, or digitally via this link.

The increasing complexity of modern communication systems has resulted in optimising several different technologies for each specific function. Hence, such communication systems comprise many chips. The downscaling of Si CMOS technology has allowed for a large-scale integration level that includes the integration of high-speed transceivers on the chips. Nevertheless, the low-voltage operation of CMOS technology cannot meet the requirements of high-power, high-efficiency power amplifiers. Thus, alternate materials are of interest for power amplifier applications. GaN is one promising candidate based on its ability to operate at high frequency and power levels. However, RF Front-End Modules (RF-FEMs) include high-performance switches fabricated on semi-insulating substrates. Therefore, realising the next generations of power and cost-efficient RF systems depends highly on the co-integration of the different device technologies.

The main target of this work is the optimisation of GaN-on-Si HEMTs for use in such high-performance communication systems. This thesis tackles that by first enhancing AlCu-based gate-metal stacks in a gate-first process to mitigate the plausibility of the gate resistance becoming a limitation to the cut-off frequency of the unilateral gain (fmax). The procedure of optimising the gate-metal stack utilises small-signal RF characterisation and modelling in addition to developing a gate resistance model, which accounts for the Tshape geometry of the gate. Such modelling is necessary, given that gate resistance models and extraction methods for CMOS devices do not account for the asymmetric nature of the T-gate in GaN HEMTs. After optimising the gate-metal stack, nonlinear and large-signal characterisation, combined with small-signal equivalent circuit modelling, provide insight into the linearity trade-offs associated with varying T-gate geometries. A substantial portion of this work focuses on the compromises related to different vertical layers, namely the channel thickness and the top barrier layer. Downscaling the gate lengths below 150nm enables a higher gain, which thus facilitates superior high-frequency operation. However, shorter gate lengths may increase short-channel effects. Investigating various thinned-down barrier materials, using RF small- and large-signal characterisation, reveals the necessity of improving the device linearity for thinner top barriers by lowering the source access resistance and suppressing the gate leakage. Examining the impact of thinner channel thicknesses, in the presence of a cGaN back-barrier, on the large-signal device performance clarifies a significant trade-off between short-channel effect suppression and efficient power performance, since the rise in current collapse and dispersion negatively impacts the large-signal metrics by increasing the knee voltage and reducing the maximum current. Carefully designing a composite backbarrier can alleviate some of the on-resistance, thus enhancing the output power of thin-channel downscaled devices.

Finally, the findings of this thesis provide guidelines for GaN-on-Si technology optimisation depending on the target frequency band of operation.

Recently a consortium coordinated by Post Factum with ETRO-VUB as a subcontractor, could win a public tender for a  framework contract for the period 2024-2027, in the field of e-health and biomedical engineering for the multiple partners in the health sector of 14 African countries. The framework contract is funded by ENABEL, the development agency of Belgium’s federal government. Projects will be executed at various level form national level to sector level down to institutional level in the field of biomedical engineering, digital strategies and solutions for the development of national e-health programs including the security of confidential data and capacity building.  

With this framework contract, next to its already many rolled out international VLIR-UOS projects, the ETRO-department can further pursue its role in global societal responsibility and sustainability. It will reinforce it international presence in low and medium income countries in the broad domain of biomedical engineering and health technologies.

For more information about our activities in broad domain of biomedical engineering in LMI countries, please take contact with Prof. Johan Stiens

Participating ETRO professors from the BME field and their teams: Prof. Johan Stiens, Prof. Jef Vandemeulebroucke, Prof. Bart Jansen, Prof. Bruno da Silva  

Dear colleagues,

     We’re pleased to announce that the AI4WCM research team will be hosting a presentation in the Marconi meeting room at PL9.2 on the 16th of October from 13:30 to 14:30. During this one-hour session, each team member will share their latest research and findings in a relaxed and informative manner. It’s a great opportunity to stay updated on the work happening within our group.

     Please mark your calendars and keep an eye out for more details. We look forward to sharing our research progress with you!

ETRO contributes via Johan Stiens, as member of the  AIOTI Digital for Climate Task Force, to the second release of the carbon footprint measurement methodology for users of IoT and Edge Computing technologies and services

The Report is structured to present rules and regulations of the European Green Deal, the initiatives and standards, and existing methodologies of measuring ICT carbon footprint. The report also includes how those methodologies can be applied to IoT and Edge Computing, the description of the methodologies, selection criteria and how to measure benefits of using them in reducing carbon footprint by using IoT and Edge Computing technologies and services for several industrial domains.

This second version of the report updates the equations that were introduced in version (Release 1.1) of the Report, which address the calculation of avoided carbon emissions in industrial sectors when ICT is applied by focusing on:

• a baseline (industrial) scenario that is supported by an ICT solution and a green enabled (industrial) scenario that apply an advanced ICT solution to reduce carbon emissions in the same industrial scenario,
• the impact that a closed loop recycling/allocation process has on these equations.

Weblink to the full report: https://aioti.eu/iot-and-edge-computing-carbon-footprint-measurement-methodology-report-release-2/

On October 13th 2023 at 15.30, Johan Hoang-Dung Nguyen will defend his PhD entitled “HIGH-EFFICIENCY TRANSMITTERS FOR 5G COMMUNICATION AT MMWAVE FREQUENCIES”.

Everybody is invited to attend the presentation at the Room D.2.01, or digitally via this link.

The fifth generation (5G) wireless communication technology started its deployment in 2019 to meet the increasing global demands for highspeed connectivity. The radio frequency spectrum will be progressively expanded to millimeter-wave ranges to meet the growing demand for mobile broadband applications. 5G targets wireless data rates of up to 10 Gbit/s. A broad deployment of applications that are based on these high data rates is only possible if the power consumption of the transmit and receive part does not grow out of hand. In a mm-wave transceiver, the transmit part often consumes most of the energy. This doctoral work focuses on the design and calibration of digital polar transmit architectures operating at mm-wave frequencies, which could bring a high data rate for less power consumption. In a polar transmitter, the signal is split in amplitude path and a phase path. The amplitude is modulated using a so-called RF-DAC, while the phase is modulated via phase modulators.

One big design achievement of this Ph.D. work is the 60-GHz digital polar chip in 28-nm Bulk CMOS. Compared to earlier digital polar transmitters operating around 60GHz, the RF-DAC used here does not suffer from leakage from disabled cells. In this way, it is possible to modulate with a higher modulation depth. Two leakage reduction techniques have been suggested from which a patent is issued: the dynamic driver and the inverter switch. The phase modulator is a Cartesian one, using a 90 degrees hybrid, that splits the input signal into an in-phase (I) and a quadrature (Q) component, which are weighted with a very linear variable gain, made with variable-gain amplifiers (VGAs). Thanks to this phase modulator and to the leakage-mitigation improvements, this chipachieves a raw data rate of 10.52 Gb/s using a 64-QAM modulation. The on-chip impedance matching is accomplished with transformers. In this work, a design flow based on ABCD matrices has been developed to speed up the design of these transformers. The same framework is later used to design a 140-GHz transceiver front-end with a transmit/receive switch.

Synchronization between the amplitude path and the phase path is vital in digital polar architectures. To facilitate and speed up this synchronization, a non-iterative method is proposed here. This strategy is then extended to retrieve and compensate AM-AM and AM-PM distortion from the VGAs. It is also possible to estimate the IQ imbalance of the hybrid. Higher bandwidths can be achieved by using the method to calculate an equalization filter for the phase samples.

Fawaz Samani received the FWO Aspirant strategisch basisonderzoek mandate with the project “Towards Human Friendly Explanations”

We have exciting news!

ETRO researchers contributed to the validation of the TraumaGuard System, the ONLY Continuous Intra-Abdominal Pressure (IAP) measurement device against four other monitoring devices in a new publication by the Journal of Clinical Medicine (JCM) MDPI. We’re on a mission to transform critical care with innovative solutions and better alternatives. A huge thank you to the brilliant minds behind this research and to all of you for being a part of our journey. Read the full article and see what makes the TraumaGuard System the only continuous IAP measurement device in the market: 

https://www.mdpi.com/2077-0383/12/19/6260 with co-authors Salar Tayebi, Ashkam Zhargami en Johan Stiens

“Signal Processing in the AI era” was the tagline of this year’s IEEE International Conference on Acoustics, Speech and Signal Processing, taking place in Rhodes, Greece.

In this context, Brent de Weerdt, Xiangyu Yang, Boris Joukovsky, Alex Stergiou and Nikos Deligiannis presented ETRO’s research during poster sessions and oral presentations, with novel ways to process and understand graph, video, and audio data. Nikos Deligiannis chaired a session on Graph Deep Learning, attended the IEEE T-IP Editorial Board Meeting, and had the opportunity to meet with collaborators from the VUB-Duke-Ugent-UCL joint lab.

Featured articles:

• De Weerdt, B. et al., “Designing Transformer Networks for Sparse Recovery of Sequential Data Using Deep Unfolding” (https://ieeexplore.ieee.org/abstract/document/10094712)
• Yang X. et al., “Relevance Propagation through Deep Conditional Random Fields” (https://ieeexplore.ieee.org/abstract/document/10095075)
• Stergiou A. et al., “Play it back: Iterative attention for audio recognition” (https://ieeexplore.ieee.org/abstract/document/10096532, developed at the University of Bristol)

The ETRO team, comprising Salar Tayebi, Ashkan Zarghami, Manu Malbrain, and Johan Stiens, has developed an innovative programmable abdominal phantom. This device is designed to simulate various scenarios and pathologies related to ICU patients. Recently showcased at the 13th International Fluid Academy Days in Antwerp, it marks a significant step forward in the realm of medical training and research. This abdominal phantom is primarily aimed at enhancing the training experience for nurses and engineering students, providing them with a more hands-on and realistic learning environment. Additionally, it holds potential for use in validating medical equipment and facilitating research and development in medical technologies. Its introduction to the medical doctors’ ecosystem underscores its relevance and utility in contemporary medical education and practice

Guest vouchers for the VUB(next) wifi network should be asked 24 hours in advance at the service desk of VUB (SNOW). The request form can be found at https://vub.service-now.com.

In case of emergency (you forgot to request the vouchers) you can
– call VUB ICT Service Desk +32 (0) 2 629 37 37 or
– render them a visit PL9 5^th floor.
With some luck they will make the needed vouchers instantly.

You van visit the LEGO urban planner again and design your climate-resilient city at “Dag van de Wetenschap” (Science Day) on Sunday 26 November at Muntpunt.

The I Love Science Festival at Tour & Taxis in Brussels on October 13-15 was a great success, drawing over 150000 science and technology enthusiasts of all ages. ETRO.RDI enchanted attendees with interactive exhibits, including light-based physiological readings, acoustic camera art, a crypto escape room challenge, and an AI-driven urban climate model.

For those who missed out on this year’s event, mark your calendars for the next I Love Science Festival, and be sure to check out ETRO.RDI’s booths.

On October 6th 2023 at 17.00, Rana ElKashlan will defend her PhD entitled “GAN-ON-SI TECHNOLOGY FOR MODERN WIRELESS COMMUNICATION SYSTEMS: OPTIMISATION INSIGHT USING RF CHARACTERISATION”.

Everybody is invited to attend the presentation at the Room D.2.01, or digitally via this link.

The increasing complexity of modern communication systems has resulted in optimising several different technologies for each specific function. Hence, such communication systems comprise many chips. The downscaling of Si CMOS technology has allowed for a large-scale integration level that includes the integration of high-speed transceivers on the chips. Nevertheless, the low-voltage operation of CMOS technology cannot meet the requirements of high-power, high-efficiency power amplifiers. Thus, alternate materials are of interest for power amplifier applications. GaN is one promising candidate based on its ability to operate at high frequency and power levels. However, RF Front-End Modules (RF-FEMs) include high-performance switches fabricated on semi-insulating substrates. Therefore, realising the next generations of power and cost-efficient RF systems depends highly on the co-integration of the different device technologies.

The main target of this work is the optimisation of GaN-on-Si HEMTs for use in such high-performance communication systems. This thesis tackles that by first enhancing AlCu-based gate-metal stacks in a gate-first process to mitigate the plausibility of the gate resistance becoming a limitation to the cut-off frequency of the unilateral gain (fmax). The procedure of optimising the gate-metal stack utilises small-signal RF characterisation and modelling in addition to developing a gate resistance model, which accounts for the Tshape geometry of the gate. Such modelling is necessary, given that gate resistance models and extraction methods for CMOS devices do not account for the asymmetric nature of the T-gate in GaN HEMTs. After optimising the gate-metal stack, nonlinear and large-signal characterisation, combined with small-signal equivalent circuit modelling, provide insight into the linearity trade-offs associated with varying T-gate geometries. A substantial portion of this work focuses on the compromises related to different vertical layers, namely the channel thickness and the top barrier layer. Downscaling the gate lengths below 150nm enables a higher gain, which thus facilitates superior high-frequency operation. However, shorter gate lengths may increase short-channel effects. Investigating various thinned-down barrier materials, using RF small- and large-signal characterisation, reveals the necessity of improving the device linearity for thinner top barriers by lowering the source access resistance and suppressing the gate leakage. Examining the impact of thinner channel thicknesses, in the presence of a cGaN back-barrier, on the large-signal device performance clarifies a significant trade-off between short-channel effect suppression and efficient power performance, since the rise in current collapse and dispersion negatively impacts the large-signal metrics by increasing the knee voltage and reducing the maximum current. Carefully designing a composite backbarrier can alleviate some of the on-resistance, thus enhancing the output power of thin-channel downscaled devices.

Finally, the findings of this thesis provide guidelines for GaN-on-Si technology optimisation depending on the target frequency band of operation.

Recently a consortium coordinated by Post Factum with ETRO-VUB as a subcontractor, could win a public tender for a  framework contract for the period 2024-2027, in the field of e-health and biomedical engineering for the multiple partners in the health sector of 14 African countries. The framework contract is funded by ENABEL, the development agency of Belgium’s federal government. Projects will be executed at various level form national level to sector level down to institutional level in the field of biomedical engineering, digital strategies and solutions for the development of national e-health programs including the security of confidential data and capacity building.  

With this framework contract, next to its already many rolled out international VLIR-UOS projects, the ETRO-department can further pursue its role in global societal responsibility and sustainability. It will reinforce it international presence in low and medium income countries in the broad domain of biomedical engineering and health technologies.

For more information about our activities in broad domain of biomedical engineering in LMI countries, please take contact with Prof. Johan Stiens

Participating ETRO professors from the BME field and their teams: Prof. Johan Stiens, Prof. Jef Vandemeulebroucke, Prof. Bart Jansen, Prof. Bruno da Silva  

Dear colleagues,

     We’re pleased to announce that the AI4WCM research team will be hosting a presentation in the Marconi meeting room at PL9.2 on the 16th of October from 13:30 to 14:30. During this one-hour session, each team member will share their latest research and findings in a relaxed and informative manner. It’s a great opportunity to stay updated on the work happening within our group.

     Please mark your calendars and keep an eye out for more details. We look forward to sharing our research progress with you!

ETRO contributes via Johan Stiens, as member of the  AIOTI Digital for Climate Task Force, to the second release of the carbon footprint measurement methodology for users of IoT and Edge Computing technologies and services

The Report is structured to present rules and regulations of the European Green Deal, the initiatives and standards, and existing methodologies of measuring ICT carbon footprint. The report also includes how those methodologies can be applied to IoT and Edge Computing, the description of the methodologies, selection criteria and how to measure benefits of using them in reducing carbon footprint by using IoT and Edge Computing technologies and services for several industrial domains.

This second version of the report updates the equations that were introduced in version (Release 1.1) of the Report, which address the calculation of avoided carbon emissions in industrial sectors when ICT is applied by focusing on:

• a baseline (industrial) scenario that is supported by an ICT solution and a green enabled (industrial) scenario that apply an advanced ICT solution to reduce carbon emissions in the same industrial scenario,
• the impact that a closed loop recycling/allocation process has on these equations.

Weblink to the full report: https://aioti.eu/iot-and-edge-computing-carbon-footprint-measurement-methodology-report-release-2/

On October 13th 2023 at 15.30, Johan Hoang-Dung Nguyen will defend his PhD entitled “HIGH-EFFICIENCY TRANSMITTERS FOR 5G COMMUNICATION AT MMWAVE FREQUENCIES”.

Everybody is invited to attend the presentation at the Room D.2.01, or digitally via this link.

The fifth generation (5G) wireless communication technology started its deployment in 2019 to meet the increasing global demands for highspeed connectivity. The radio frequency spectrum will be progressively expanded to millimeter-wave ranges to meet the growing demand for mobile broadband applications. 5G targets wireless data rates of up to 10 Gbit/s. A broad deployment of applications that are based on these high data rates is only possible if the power consumption of the transmit and receive part does not grow out of hand. In a mm-wave transceiver, the transmit part often consumes most of the energy. This doctoral work focuses on the design and calibration of digital polar transmit architectures operating at mm-wave frequencies, which could bring a high data rate for less power consumption. In a polar transmitter, the signal is split in amplitude path and a phase path. The amplitude is modulated using a so-called RF-DAC, while the phase is modulated via phase modulators.

One big design achievement of this Ph.D. work is the 60-GHz digital polar chip in 28-nm Bulk CMOS. Compared to earlier digital polar transmitters operating around 60GHz, the RF-DAC used here does not suffer from leakage from disabled cells. In this way, it is possible to modulate with a higher modulation depth. Two leakage reduction techniques have been suggested from which a patent is issued: the dynamic driver and the inverter switch. The phase modulator is a Cartesian one, using a 90 degrees hybrid, that splits the input signal into an in-phase (I) and a quadrature (Q) component, which are weighted with a very linear variable gain, made with variable-gain amplifiers (VGAs). Thanks to this phase modulator and to the leakage-mitigation improvements, this chipachieves a raw data rate of 10.52 Gb/s using a 64-QAM modulation. The on-chip impedance matching is accomplished with transformers. In this work, a design flow based on ABCD matrices has been developed to speed up the design of these transformers. The same framework is later used to design a 140-GHz transceiver front-end with a transmit/receive switch.

Synchronization between the amplitude path and the phase path is vital in digital polar architectures. To facilitate and speed up this synchronization, a non-iterative method is proposed here. This strategy is then extended to retrieve and compensate AM-AM and AM-PM distortion from the VGAs. It is also possible to estimate the IQ imbalance of the hybrid. Higher bandwidths can be achieved by using the method to calculate an equalization filter for the phase samples.

Fawaz Samani received the FWO Aspirant strategisch basisonderzoek mandate with the project “Towards Human Friendly Explanations”

We have exciting news!

ETRO researchers contributed to the validation of the TraumaGuard System, the ONLY Continuous Intra-Abdominal Pressure (IAP) measurement device against four other monitoring devices in a new publication by the Journal of Clinical Medicine (JCM) MDPI. We’re on a mission to transform critical care with innovative solutions and better alternatives. A huge thank you to the brilliant minds behind this research and to all of you for being a part of our journey. Read the full article and see what makes the TraumaGuard System the only continuous IAP measurement device in the market: 

https://www.mdpi.com/2077-0383/12/19/6260 with co-authors Salar Tayebi, Ashkam Zhargami en Johan Stiens

“Signal Processing in the AI era” was the tagline of this year’s IEEE International Conference on Acoustics, Speech and Signal Processing, taking place in Rhodes, Greece.

In this context, Brent de Weerdt, Xiangyu Yang, Boris Joukovsky, Alex Stergiou and Nikos Deligiannis presented ETRO’s research during poster sessions and oral presentations, with novel ways to process and understand graph, video, and audio data. Nikos Deligiannis chaired a session on Graph Deep Learning, attended the IEEE T-IP Editorial Board Meeting, and had the opportunity to meet with collaborators from the VUB-Duke-Ugent-UCL joint lab.

Featured articles:

• De Weerdt, B. et al., “Designing Transformer Networks for Sparse Recovery of Sequential Data Using Deep Unfolding” (https://ieeexplore.ieee.org/abstract/document/10094712)
• Yang X. et al., “Relevance Propagation through Deep Conditional Random Fields” (https://ieeexplore.ieee.org/abstract/document/10095075)
• Stergiou A. et al., “Play it back: Iterative attention for audio recognition” (https://ieeexplore.ieee.org/abstract/document/10096532, developed at the University of Bristol)

The ETRO team, comprising Salar Tayebi, Ashkan Zarghami, Manu Malbrain, and Johan Stiens, has developed an innovative programmable abdominal phantom. This device is designed to simulate various scenarios and pathologies related to ICU patients. Recently showcased at the 13th International Fluid Academy Days in Antwerp, it marks a significant step forward in the realm of medical training and research. This abdominal phantom is primarily aimed at enhancing the training experience for nurses and engineering students, providing them with a more hands-on and realistic learning environment. Additionally, it holds potential for use in validating medical equipment and facilitating research and development in medical technologies. Its introduction to the medical doctors’ ecosystem underscores its relevance and utility in contemporary medical education and practice

Guest vouchers for the VUB(next) wifi network should be asked 24 hours in advance at the service desk of VUB (SNOW). The request form can be found at https://vub.service-now.com.

In case of emergency (you forgot to request the vouchers) you can
– call VUB ICT Service Desk +32 (0) 2 629 37 37 or
– render them a visit PL9 5^th floor.
With some luck they will make the needed vouchers instantly.

You van visit the LEGO urban planner again and design your climate-resilient city at “Dag van de Wetenschap” (Science Day) on Sunday 26 November at Muntpunt.

The I Love Science Festival at Tour & Taxis in Brussels on October 13-15 was a great success, drawing over 150000 science and technology enthusiasts of all ages. ETRO.RDI enchanted attendees with interactive exhibits, including light-based physiological readings, acoustic camera art, a crypto escape room challenge, and an AI-driven urban climate model.

For those who missed out on this year’s event, mark your calendars for the next I Love Science Festival, and be sure to check out ETRO.RDI’s booths.

On October 6th 2023 at 17.00, Rana ElKashlan will defend her PhD entitled “GAN-ON-SI TECHNOLOGY FOR MODERN WIRELESS COMMUNICATION SYSTEMS: OPTIMISATION INSIGHT USING RF CHARACTERISATION”.

Everybody is invited to attend the presentation at the Room D.2.01, or digitally via this link.

The increasing complexity of modern communication systems has resulted in optimising several different technologies for each specific function. Hence, such communication systems comprise many chips. The downscaling of Si CMOS technology has allowed for a large-scale integration level that includes the integration of high-speed transceivers on the chips. Nevertheless, the low-voltage operation of CMOS technology cannot meet the requirements of high-power, high-efficiency power amplifiers. Thus, alternate materials are of interest for power amplifier applications. GaN is one promising candidate based on its ability to operate at high frequency and power levels. However, RF Front-End Modules (RF-FEMs) include high-performance switches fabricated on semi-insulating substrates. Therefore, realising the next generations of power and cost-efficient RF systems depends highly on the co-integration of the different device technologies.

The main target of this work is the optimisation of GaN-on-Si HEMTs for use in such high-performance communication systems. This thesis tackles that by first enhancing AlCu-based gate-metal stacks in a gate-first process to mitigate the plausibility of the gate resistance becoming a limitation to the cut-off frequency of the unilateral gain (fmax). The procedure of optimising the gate-metal stack utilises small-signal RF characterisation and modelling in addition to developing a gate resistance model, which accounts for the Tshape geometry of the gate. Such modelling is necessary, given that gate resistance models and extraction methods for CMOS devices do not account for the asymmetric nature of the T-gate in GaN HEMTs. After optimising the gate-metal stack, nonlinear and large-signal characterisation, combined with small-signal equivalent circuit modelling, provide insight into the linearity trade-offs associated with varying T-gate geometries. A substantial portion of this work focuses on the compromises related to different vertical layers, namely the channel thickness and the top barrier layer. Downscaling the gate lengths below 150nm enables a higher gain, which thus facilitates superior high-frequency operation. However, shorter gate lengths may increase short-channel effects. Investigating various thinned-down barrier materials, using RF small- and large-signal characterisation, reveals the necessity of improving the device linearity for thinner top barriers by lowering the source access resistance and suppressing the gate leakage. Examining the impact of thinner channel thicknesses, in the presence of a cGaN back-barrier, on the large-signal device performance clarifies a significant trade-off between short-channel effect suppression and efficient power performance, since the rise in current collapse and dispersion negatively impacts the large-signal metrics by increasing the knee voltage and reducing the maximum current. Carefully designing a composite backbarrier can alleviate some of the on-resistance, thus enhancing the output power of thin-channel downscaled devices.

Finally, the findings of this thesis provide guidelines for GaN-on-Si technology optimisation depending on the target frequency band of operation.

Recently a consortium coordinated by Post Factum with ETRO-VUB as a subcontractor, could win a public tender for a  framework contract for the period 2024-2027, in the field of e-health and biomedical engineering for the multiple partners in the health sector of 14 African countries. The framework contract is funded by ENABEL, the development agency of Belgium’s federal government. Projects will be executed at various level form national level to sector level down to institutional level in the field of biomedical engineering, digital strategies and solutions for the development of national e-health programs including the security of confidential data and capacity building.  

With this framework contract, next to its already many rolled out international VLIR-UOS projects, the ETRO-department can further pursue its role in global societal responsibility and sustainability. It will reinforce it international presence in low and medium income countries in the broad domain of biomedical engineering and health technologies.

For more information about our activities in broad domain of biomedical engineering in LMI countries, please take contact with Prof. Johan Stiens

Participating ETRO professors from the BME field and their teams: Prof. Johan Stiens, Prof. Jef Vandemeulebroucke, Prof. Bart Jansen, Prof. Bruno da Silva  

Dear colleagues,

     We’re pleased to announce that the AI4WCM research team will be hosting a presentation in the Marconi meeting room at PL9.2 on the 16th of October from 13:30 to 14:30. During this one-hour session, each team member will share their latest research and findings in a relaxed and informative manner. It’s a great opportunity to stay updated on the work happening within our group.

     Please mark your calendars and keep an eye out for more details. We look forward to sharing our research progress with you!

ETRO contributes via Johan Stiens, as member of the  AIOTI Digital for Climate Task Force, to the second release of the carbon footprint measurement methodology for users of IoT and Edge Computing technologies and services

The Report is structured to present rules and regulations of the European Green Deal, the initiatives and standards, and existing methodologies of measuring ICT carbon footprint. The report also includes how those methodologies can be applied to IoT and Edge Computing, the description of the methodologies, selection criteria and how to measure benefits of using them in reducing carbon footprint by using IoT and Edge Computing technologies and services for several industrial domains.

This second version of the report updates the equations that were introduced in version (Release 1.1) of the Report, which address the calculation of avoided carbon emissions in industrial sectors when ICT is applied by focusing on:

• a baseline (industrial) scenario that is supported by an ICT solution and a green enabled (industrial) scenario that apply an advanced ICT solution to reduce carbon emissions in the same industrial scenario,
• the impact that a closed loop recycling/allocation process has on these equations.

Weblink to the full report: https://aioti.eu/iot-and-edge-computing-carbon-footprint-measurement-methodology-report-release-2/

On October 13th 2023 at 15.30, Johan Hoang-Dung Nguyen will defend his PhD entitled “HIGH-EFFICIENCY TRANSMITTERS FOR 5G COMMUNICATION AT MMWAVE FREQUENCIES”.

Everybody is invited to attend the presentation at the Room D.2.01, or digitally via this link.

The fifth generation (5G) wireless communication technology started its deployment in 2019 to meet the increasing global demands for highspeed connectivity. The radio frequency spectrum will be progressively expanded to millimeter-wave ranges to meet the growing demand for mobile broadband applications. 5G targets wireless data rates of up to 10 Gbit/s. A broad deployment of applications that are based on these high data rates is only possible if the power consumption of the transmit and receive part does not grow out of hand. In a mm-wave transceiver, the transmit part often consumes most of the energy. This doctoral work focuses on the design and calibration of digital polar transmit architectures operating at mm-wave frequencies, which could bring a high data rate for less power consumption. In a polar transmitter, the signal is split in amplitude path and a phase path. The amplitude is modulated using a so-called RF-DAC, while the phase is modulated via phase modulators.

One big design achievement of this Ph.D. work is the 60-GHz digital polar chip in 28-nm Bulk CMOS. Compared to earlier digital polar transmitters operating around 60GHz, the RF-DAC used here does not suffer from leakage from disabled cells. In this way, it is possible to modulate with a higher modulation depth. Two leakage reduction techniques have been suggested from which a patent is issued: the dynamic driver and the inverter switch. The phase modulator is a Cartesian one, using a 90 degrees hybrid, that splits the input signal into an in-phase (I) and a quadrature (Q) component, which are weighted with a very linear variable gain, made with variable-gain amplifiers (VGAs). Thanks to this phase modulator and to the leakage-mitigation improvements, this chipachieves a raw data rate of 10.52 Gb/s using a 64-QAM modulation. The on-chip impedance matching is accomplished with transformers. In this work, a design flow based on ABCD matrices has been developed to speed up the design of these transformers. The same framework is later used to design a 140-GHz transceiver front-end with a transmit/receive switch.

Synchronization between the amplitude path and the phase path is vital in digital polar architectures. To facilitate and speed up this synchronization, a non-iterative method is proposed here. This strategy is then extended to retrieve and compensate AM-AM and AM-PM distortion from the VGAs. It is also possible to estimate the IQ imbalance of the hybrid. Higher bandwidths can be achieved by using the method to calculate an equalization filter for the phase samples.

Fawaz Samani received the FWO Aspirant strategisch basisonderzoek mandate with the project “Towards Human Friendly Explanations”

We have exciting news!

ETRO researchers contributed to the validation of the TraumaGuard System, the ONLY Continuous Intra-Abdominal Pressure (IAP) measurement device against four other monitoring devices in a new publication by the Journal of Clinical Medicine (JCM) MDPI. We’re on a mission to transform critical care with innovative solutions and better alternatives. A huge thank you to the brilliant minds behind this research and to all of you for being a part of our journey. Read the full article and see what makes the TraumaGuard System the only continuous IAP measurement device in the market: 

https://www.mdpi.com/2077-0383/12/19/6260 with co-authors Salar Tayebi, Ashkam Zhargami en Johan Stiens