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Roelof Bernardus Timens
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3 records found
1
Journal article
(2019)
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Laurens Bliek, Sander Wahls, Ilka Visscher, Caterina Taddei, Roelof Bernardus Timens, Ruud Oldenbeuving, Chris Roeloffzen, Michel Verhaegen
We present a novel photonic beamformer for a fully integrated transmit phased array antenna, together with an automatic procedure for tuning the delays in this system. Such an automatic tuning procedure is required because the large number of actuators makes manual tuning practically impossible. The antenna system is designed for the purpose of the broadband aircraft-satellite communication in the \mathrm{K_u}-band to provide satellite Internet connections on board the aircraft. The goal of the beamformer is to automatically steer the transmit antenna electronically in the direction of the satellite. This is done using a mix of phase shifters and tunable optical delay lines, which are all integrated on a chip and laid out in a tree structure. The \mathrm{K_u}-band has a bandwidth of 0.5 GHz. We show how an optical delay line is automatically configured over this bandwidth, providing a delay of approximately 0.4 ns. The tuning algorithm calculates the best actuator voltages based on past measurements. This is the first time that such an automatic tuning scheme is used on a photonic beamformer for this type of transmit phased array antenna. We show that the proposed method is able to provide accurate beamforming ({<}\text{11.25}^{\circ} phase error over the whole bandwidth) for two different delay settings.
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We present a novel photonic beamformer for a fully integrated transmit phased array antenna, together with an automatic procedure for tuning the delays in this system. Such an automatic tuning procedure is required because the large number of actuators makes manual tuning practically impossible. The antenna system is designed for the purpose of the broadband aircraft-satellite communication in the \mathrm{K_u}-band to provide satellite Internet connections on board the aircraft. The goal of the beamformer is to automatically steer the transmit antenna electronically in the direction of the satellite. This is done using a mix of phase shifters and tunable optical delay lines, which are all integrated on a chip and laid out in a tree structure. The \mathrm{K_u}-band has a bandwidth of 0.5 GHz. We show how an optical delay line is automatically configured over this bandwidth, providing a delay of approximately 0.4 ns. The tuning algorithm calculates the best actuator voltages based on past measurements. This is the first time that such an automatic tuning scheme is used on a photonic beamformer for this type of transmit phased array antenna. We show that the proposed method is able to provide accurate beamforming ({<}\text{11.25}^{\circ} phase error over the whole bandwidth) for two different delay settings.
Conference paper
(2018)
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Chris Roeloffzen, Ilka Visscher, Robert Grootjans, Laurens Bliek, Sander Wahls, Michel Verhaegen, Caterina Taddei, Dimitri Geskus, Ruud Oldenbeuving, Jörn Epping, Roelof Bernardus Timens, Paul van Dijk, René Heideman, Marcel Hoekman
This paper describes the design, fabrication, packaging, testing and automated tuning of an integrated 1x4 optical beamforming network. It consists of hybridly integrated InP and TriPleX chips, where end-facet coupling is used for optical interfacing.
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This paper describes the design, fabrication, packaging, testing and automated tuning of an integrated 1x4 optical beamforming network. It consists of hybridly integrated InP and TriPleX chips, where end-facet coupling is used for optical interfacing.
Conference paper
(2017)
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Laurens Bliek, Hans Verstraete, Sander Wahls, Roelof Bernardus Timens, Ruud Oldenbeuving, Chris Roeloffzen, Michel Verhaegen
In recent years we have seen a rise in the amount of fitness tracking and self monitoring devices. These devices which often work in conjunction with a smartphone are becoming more accurate and are becoming widely adopted. This trend goes hand in hand with Electronic Health Care (e-health): the shift of health care to the digital domain. E-health would allow patients to measure their medical condition at home, allowing a diagnosis to be made based on measurements taken over a longer period of time, while reducing the work performed by a doctor. Measurements are tored in the cloud, simplifying the way in which they can be shared with healthcare providers and possibly research nstitutions. Modernizing healthcare this way should give the patient more insight and control over his/her healthcare and medical data. Furthermore the amount of visits required to the hospital can be reduced, an endeavor which can be demanding for many less fit for elderly individuals.
However, handling medical data this way causes concern for privacy. Often the data handled by these devices is very sensitive and could easily be used to identify the user and monitor many of their behaviours. In order to achieve privacy there are several approaches. One way is to enforce involved parties through legislation to use the data for specific purposes only. However, this relies on the party being semi-trusted and does not guarantee safety in case of a data-breach.
In this work the way in which the integration of wearables into the medical domain is currently taking place and how privacy and security is handled will be explored. Furthermore we will show the current state of research regarding improving this security.
...
In recent years we have seen a rise in the amount of fitness tracking and self monitoring devices. These devices which often work in conjunction with a smartphone are becoming more accurate and are becoming widely adopted. This trend goes hand in hand with Electronic Health Care (e-health): the shift of health care to the digital domain. E-health would allow patients to measure their medical condition at home, allowing a diagnosis to be made based on measurements taken over a longer period of time, while reducing the work performed by a doctor. Measurements are tored in the cloud, simplifying the way in which they can be shared with healthcare providers and possibly research nstitutions. Modernizing healthcare this way should give the patient more insight and control over his/her healthcare and medical data. Furthermore the amount of visits required to the hospital can be reduced, an endeavor which can be demanding for many less fit for elderly individuals.
However, handling medical data this way causes concern for privacy. Often the data handled by these devices is very sensitive and could easily be used to identify the user and monitor many of their behaviours. In order to achieve privacy there are several approaches. One way is to enforce involved parties through legislation to use the data for specific purposes only. However, this relies on the party being semi-trusted and does not guarantee safety in case of a data-breach.
In this work the way in which the integration of wearables into the medical domain is currently taking place and how privacy and security is handled will be explored. Furthermore we will show the current state of research regarding improving this security.