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A textile, embroidered antenna, based on the fractal shape of the Sierpinski triangle, is designed in this paper for operation in the European free Industrial Scientific and Medical (ISM) 863–870 MHz band, as well as in the 902–928 MHz band designated for ISM applications in North and South America. Several prototypes have been fabricated by employing different stitch patterns and thread materials. The effect of the fabrication parameters on the performance of the proposed antenna is investigated through measurements and simulations, with the results being in good agreement. The antenna exhibits attractive characteristics such as wide bandwidth, relatively stable radiation patterns, as well as robustness in washing. Several tests reveal that convex and concave bent conditions do not affect the coverage of the aforementioned ISM bands, despite the shift of the resonant frequency in some cases. Moreover, the SAR values resulting from simulations are below the corresponding thresholds suggested by international guidelines.
Theodoros N. Kapetanakis; Martin Pavec; Melina P. Ioannidou; Christos D. Nikolopoulos; Anargyros T. Baklezos; Radek Soukup; Ioannis O. Vardiambasis. Embroidered Βow-Tie Wearable Antenna for the 868 and 915 MHz ISM Bands. Electronics 2021, 10, 1983 .
AMA StyleTheodoros N. Kapetanakis, Martin Pavec, Melina P. Ioannidou, Christos D. Nikolopoulos, Anargyros T. Baklezos, Radek Soukup, Ioannis O. Vardiambasis. Embroidered Βow-Tie Wearable Antenna for the 868 and 915 MHz ISM Bands. Electronics. 2021; 10 (16):1983.
Chicago/Turabian StyleTheodoros N. Kapetanakis; Martin Pavec; Melina P. Ioannidou; Christos D. Nikolopoulos; Anargyros T. Baklezos; Radek Soukup; Ioannis O. Vardiambasis. 2021. "Embroidered Βow-Tie Wearable Antenna for the 868 and 915 MHz ISM Bands." Electronics 10, no. 16: 1983.
Sewage sludge hydrochars (SSHs), which are produced by hydrothermal carbonization (HTC), offer a high calorific value to be applied as a biofuel. However, HTC is a complex processand the properties of the resulting product depend heavily on the process conditions and feedstock composition. In this work, we have applied artificial neural networks (ANNs) to contribute to the production of tailored SSHs for a specific application and with optimum properties. We collected data from the published literature covering the years 2014–2021, which was then fed into different ANN models where the input data (HTC temperature, process time, and the elemental content of hydrochars) were used to predict output parameters (higher heating value, (HHV) and solid yield (%)). The proposed ANN models were successful in accurately predicting both HHV and contents of C and H. While the model NN1 (based on C, H, O content) exhibited HHV predicting performance with R2 = 0.974, another model, NN2, was also able to predict HHV with R2 = 0.936 using only C and H as input. Moreover, the inverse model of NN3 (based on H, O content, and HHV) could predict C content with an R2 of 0.939.
Theodoros Kapetanakis; Ioannis Vardiambasis; Christos Nikolopoulos; Antonios Konstantaras; Trinh Trang; Duy Khuong; Toshiki Tsubota; Ramazan Keyikoglu; Alireza Khataee; Dimitrios Kalderis. Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge. Energies 2021, 14, 3000 .
AMA StyleTheodoros Kapetanakis, Ioannis Vardiambasis, Christos Nikolopoulos, Antonios Konstantaras, Trinh Trang, Duy Khuong, Toshiki Tsubota, Ramazan Keyikoglu, Alireza Khataee, Dimitrios Kalderis. Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge. Energies. 2021; 14 (11):3000.
Chicago/Turabian StyleTheodoros Kapetanakis; Ioannis Vardiambasis; Christos Nikolopoulos; Antonios Konstantaras; Trinh Trang; Duy Khuong; Toshiki Tsubota; Ramazan Keyikoglu; Alireza Khataee; Dimitrios Kalderis. 2021. "Towards Engineered Hydrochars: Application of Artificial Neural Networks in the Hydrothermal Carbonization of Sewage Sludge." Energies 14, no. 11: 3000.
The majority of the past and current ESA's, NASA's, and JAXA's science missions utilize broadly SpaceWire (SpW) Links, with Low Voltage Differential Signaling (LVDS) for the physical layer, to transfer mission data. Electromagnetic Compatibility (EMC) and Electromagnetic Interference (EMI) problems caused by harnesses' radiated emissions remain a constant open issue in every mission due to the scientific payload sensitivity. A common cause of radiated emissions from shielded cable bundles can be traced to the currents flowing on the shield of the harness. This work aims to present a complete methodology for predicting the Electric field emissions in the case of an operating SpW link, while it can be expanded to any shielded cable which utilizes LVDS. The physical and protocol layer of the link are implemented via a developed LVDS Signal emulator, handling both the characteristics of the signals at the outputs of the LVDS line drivers and the effects of their transmission across the link along with the termination scheme, in order to calculate the common mode current flowing on the shield. The radiated emissions can then be estimated considering the ground material and a detailed harness topology, employing traveling wave antenna theory. The validity of this approach is assessed by comparing the predictions with actual link radiated emissions measurements. Simulation results are in good agreement with the measurements, rendering this methodology a fast tactic for the pre-compliance procedure for the early design stage of the science space mission.
Alexandros D. Bechrakis Triantafyllos; Alexandra P. Mavropoulou; Anargyros T. Baklezos; Christos N. Capsalis; Christos D. Nikolopoulos. Towards the Prediction of SpaceWire Radiated Emissions Employing an LVDS Signal Emulator. IEEE Access 2021, 9, 34090 -34097.
AMA StyleAlexandros D. Bechrakis Triantafyllos, Alexandra P. Mavropoulou, Anargyros T. Baklezos, Christos N. Capsalis, Christos D. Nikolopoulos. Towards the Prediction of SpaceWire Radiated Emissions Employing an LVDS Signal Emulator. IEEE Access. 2021; 9 ():34090-34097.
Chicago/Turabian StyleAlexandros D. Bechrakis Triantafyllos; Alexandra P. Mavropoulou; Anargyros T. Baklezos; Christos N. Capsalis; Christos D. Nikolopoulos. 2021. "Towards the Prediction of SpaceWire Radiated Emissions Employing an LVDS Signal Emulator." IEEE Access 9, no. : 34090-34097.
Nowadays, a wide range of space missions accommodate ever-stricter electromagnetic cleanliness requirements arising either from the need for more precise measurements or from the implementation of highly sensitive equipment. Therefore, the establishment of a methodology that ensures the minimization of the electric and/or magnetic field in specific areas inside or outside the spacecraft structure is crucial. Towards this goal, the current chapter proposes that utilizing the results of a process completed during the early design stages of a mission, that is, the measurement and characterization of each implemented device, the desired elimination of the field can be achieved. In particular, the emerged electromagnetic signatures of the units are proven essential for the proposed methodology, which, using a heuristic approach, defines the optimal ordinance of the equipment that leads to system-level electromagnetic field minimization in the volume of interest. The dimensions of the devices and the effect of the conductive surfaces of the spacecraft's hull are also taken into account.
Christos D. Nikolopoulos. Recent Advances on Measuring and Modeling ELF-Radiated Emissions for Space Applications. Electric Vehicles and the Future of Energy Efficient Transportation 2021, 1 -38.
AMA StyleChristos D. Nikolopoulos. Recent Advances on Measuring and Modeling ELF-Radiated Emissions for Space Applications. Electric Vehicles and the Future of Energy Efficient Transportation. 2021; ():1-38.
Chicago/Turabian StyleChristos D. Nikolopoulos. 2021. "Recent Advances on Measuring and Modeling ELF-Radiated Emissions for Space Applications." Electric Vehicles and the Future of Energy Efficient Transportation , no. : 1-38.
Nowadays, a wide range of space missions accommodate ever-stricter electromagnetic cleanliness requirements arising either from the need for more precise measurements or from the implementation of highly sensitive equipment. Therefore, the establishment of a methodology that ensures the minimization of the electric and/or magnetic field in specific areas inside or outside the spacecraft structure is crucial. Towards this goal, the current chapter proposes that utilizing the results of a process completed during the early design stages of a mission, that is, the measurement and characterization of each implemented device, the desired elimination of the field can be achieved. In particular, the emerged electromagnetic signatures of the units are proven essential for the proposed methodology, which, using a heuristic approach, defines the optimal ordinance of the equipment that leads to system-level electromagnetic field minimization in the volume of interest. The dimensions of the devices and the effect of the conductive surfaces of the spacecraft's hull are also taken into account.
Alexandra P. Mavropoulou; Alexandros D. Bechrakis Triantafyllos; Christos D. Nikolopoulos. Aspects of Extremely Low Frequency Electric and Magnetic Cleanliness on Space Platforms. Electric Vehicles and the Future of Energy Efficient Transportation 2021, 127 -146.
AMA StyleAlexandra P. Mavropoulou, Alexandros D. Bechrakis Triantafyllos, Christos D. Nikolopoulos. Aspects of Extremely Low Frequency Electric and Magnetic Cleanliness on Space Platforms. Electric Vehicles and the Future of Energy Efficient Transportation. 2021; ():127-146.
Chicago/Turabian StyleAlexandra P. Mavropoulou; Alexandros D. Bechrakis Triantafyllos; Christos D. Nikolopoulos. 2021. "Aspects of Extremely Low Frequency Electric and Magnetic Cleanliness on Space Platforms." Electric Vehicles and the Future of Energy Efficient Transportation , no. : 127-146.
In this study, the growing scientific field of alternative biofuels was examined, with respect to hydrochars produced from renewable biomasses. Hydrochars are the solid products of hydrothermal carbonization (HTC) and their properties depend on the initial biomass and the temperature and duration of treatment. The basic (Scopus) and advanced (Citespace) analysis of literature showed that this is a dynamic research area, with several sub-fields of intense activity. The focus of researchers on sewage sludge and food waste as hydrochar precursors was highlighted and reviewed. It was established that hydrochars have improved behavior as fuels compared to these feedstocks. Food waste can be particularly useful in co-hydrothermal carbonization with ash-rich materials. In the case of sewage sludge, simultaneous P recovery from the HTC wastewater may add more value to the process. For both feedstocks, results from large-scale HTC are practically non-existent. Following the review, related data from the years 2014–2020 were retrieved and fitted into four different artificial neural networks (ANNs). Based on the elemental content, HTC temperature and time (as inputs), the higher heating values (HHVs) and yields (as outputs) could be successfully predicted, regardless of original biomass used for hydrochar production. ANN3 (based on C, O, H content, and HTC temperature) showed the optimum HHV predicting performance (R2 0.917, root mean square error 1.124), however, hydrochars’ HHVs could also be satisfactorily predicted by the C content alone (ANN1, R2 0.897, root mean square error 1.289).
Ioannis O. Vardiambasis; Theodoros N. Kapetanakis; Christos D. Nikolopoulos; Trinh Kieu Trang; Toshiki Tsubota; Ramazan Keyikoglu; Alireza Khataee; Dimitrios Kalderis. Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values. Energies 2020, 13, 4572 .
AMA StyleIoannis O. Vardiambasis, Theodoros N. Kapetanakis, Christos D. Nikolopoulos, Trinh Kieu Trang, Toshiki Tsubota, Ramazan Keyikoglu, Alireza Khataee, Dimitrios Kalderis. Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values. Energies. 2020; 13 (17):4572.
Chicago/Turabian StyleIoannis O. Vardiambasis; Theodoros N. Kapetanakis; Christos D. Nikolopoulos; Trinh Kieu Trang; Toshiki Tsubota; Ramazan Keyikoglu; Alireza Khataee; Dimitrios Kalderis. 2020. "Hydrochars as Emerging Biofuels: Recent Advances and Application of Artificial Neural Networks for the Prediction of Heating Values." Energies 13, no. 17: 4572.
Magnetic cleanliness is a severe electromagnetic compatibility topic in nearly all science space missions. Nowadays this interest is expanding from dc to the area of extremely low-frequency magnetic sources. This article presents an enhanced methodology to minimize the magnetic field at a volume in the vicinity of the spacecraft where sensitive instruments or measurement sensors are placed. A common process in early design stages of a space mission is to measure the candidate equipment separately and throughout this unit-level test campaign, a robust design of the system-level platform taking into consideration strict magnetic cleanliness requirements is developed. Based on this unit level magnetic signature characterization and through heuristic approach, the proper equipment ordinance or in case this is not possible the proper placement of compensation magnets can lead to system-level magnetic field minimization. The proposed methodology considers all the parameters of the equipment regarding dimensions, avoiding this way the overlap of the units inside the spacecraft providing feasible placement. Moreover, since the magnetic moment orientation and the center of the unit are the main optimization parameters, this methodology, when the appropriate measurements are available, can also include the induced magnetic behavior of the equipment. Authors prove with simulations that with appropriate equipment ordinance, the synthesis of a suitable electromagnetic environment is possible to be achieved.
Christos D. Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis. On Achieving Spacecraft Level Magnetic Cleanliness With Proper Equipment Ordinance of DC and ELF Magnetic Sources. IEEE Transactions on Electromagnetic Compatibility 2020, 62, 2714 -2724.
AMA StyleChristos D. Nikolopoulos, Anargyros T. Baklezos, Christos N. Capsalis. On Achieving Spacecraft Level Magnetic Cleanliness With Proper Equipment Ordinance of DC and ELF Magnetic Sources. IEEE Transactions on Electromagnetic Compatibility. 2020; 62 (6):2714-2724.
Chicago/Turabian StyleChristos D. Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis. 2020. "On Achieving Spacecraft Level Magnetic Cleanliness With Proper Equipment Ordinance of DC and ELF Magnetic Sources." IEEE Transactions on Electromagnetic Compatibility 62, no. 6: 2714-2724.
Catalytic nanoparticles play a key role in our lives and are an important tool for the transition to a more sustainable future. 85-90% of all manmade chemicals pass through at least one catalytic step. Ferromagnetic nanoparticles are used in vital reactions such as the production of hydrogen, ammonia and synthetic hydrocarbons. Understanding the properties of these catalysts is essential for the development of novel robust materials with desired functions. Potentially magnetic measurements can provide information about electronic configuration and nanoparticle size under reaction conditions. In the paper, a near field approximation is applied to the inverse measurement problem. The simulation is based on a proposed fluxgate arrangement for the detection of magnetism from cobalt-based catalytic materials. Results demonstrate that the measurement of Co-based catalysts is possible at low sample amounts <1 gr and from distances that allow space for conditioning equipment such as temperature supply and control or a secondary measuring arrangement.
Nikolaos Tsakoumis; Ioannis O. Vardiambasis; Christos Nikolopoulos; Anargyros T. Baklezos; Theodoros N. Kapetanakis. Fluxgate Configuration for Obtaining Magnetic Properties of Catalytic Nanoparticles: A Feasibility Study. 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) 2020, 1 -5.
AMA StyleNikolaos Tsakoumis, Ioannis O. Vardiambasis, Christos Nikolopoulos, Anargyros T. Baklezos, Theodoros N. Kapetanakis. Fluxgate Configuration for Obtaining Magnetic Properties of Catalytic Nanoparticles: A Feasibility Study. 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). 2020; ():1-5.
Chicago/Turabian StyleNikolaos Tsakoumis; Ioannis O. Vardiambasis; Christos Nikolopoulos; Anargyros T. Baklezos; Theodoros N. Kapetanakis. 2020. "Fluxgate Configuration for Obtaining Magnetic Properties of Catalytic Nanoparticles: A Feasibility Study." 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) , no. : 1-5.
In the present work, authors present measurements of the radiated emissions for different data rates of Space Wire signaling and various payloads. The test campaign is based on the military-standard and a novel approach to assemble a model appropriate for electromagnetic compatibility assessment is proposed. Authors improve upon a previous work the modeling approach including all identified skew effects of the link. These effects are the main sources of common-mode currents which are the key mechanism for the radiated emissions of the harnesses.
Anargyros T. Baklezos; Christos Nikolopoulos; Ilias R. Sigalas; Christos N. Capsalis. Measurement and Modeling of SpaceWire Radiation for Electromagnetic Compatibility Assessment. 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) 2020, 1 -5.
AMA StyleAnargyros T. Baklezos, Christos Nikolopoulos, Ilias R. Sigalas, Christos N. Capsalis. Measurement and Modeling of SpaceWire Radiation for Electromagnetic Compatibility Assessment. 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC). 2020; ():1-5.
Chicago/Turabian StyleAnargyros T. Baklezos; Christos Nikolopoulos; Ilias R. Sigalas; Christos N. Capsalis. 2020. "Measurement and Modeling of SpaceWire Radiation for Electromagnetic Compatibility Assessment." 2020 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) , no. : 1-5.
A constant electromagnetic compatibility issue in the majority of space missions is the accurate EMI source identification and modeling. This is necessary in order to provide electromagnetic (EM) cleanliness in a specific area inside or outside the spacecraft, where sensitive measurement equipment is placed. Authors in previous work have presented a stochastic process capable to accurately predict the EM signature of a device both for transient and steady-state emissions. In this article, a supplementary methodology is proposed, using the models from the previously established process, to achieve electromagnetic cleanliness. Authors claim that EM cleanliness is possible to be achieved inside or outside a specific area of the spacecraft structure with proper equipment ordinance and if necessary the aid of an additional auxiliary source. The proposed methodology is using a heuristic approach to find the optimum positions of the available equipment. The equipment when placed at these positions presents a minimum total electromagnetic field at a specific point or region. Moreover, if necessary, the total field can be further minimized with the addition of an auxiliary source.
Grigorios I. Koutantos; Christos D. Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis. Proper Equipment Ordinance for Achieving EM Cleanliness in Space Missions: The Case of ELF Electric Sources. IEEE Transactions on Electromagnetic Compatibility 2019, 62, 1686 -1692.
AMA StyleGrigorios I. Koutantos, Christos D. Nikolopoulos, Anargyros T. Baklezos, Christos N. Capsalis. Proper Equipment Ordinance for Achieving EM Cleanliness in Space Missions: The Case of ELF Electric Sources. IEEE Transactions on Electromagnetic Compatibility. 2019; 62 (5):1686-1692.
Chicago/Turabian StyleGrigorios I. Koutantos; Christos D. Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis. 2019. "Proper Equipment Ordinance for Achieving EM Cleanliness in Space Missions: The Case of ELF Electric Sources." IEEE Transactions on Electromagnetic Compatibility 62, no. 5: 1686-1692.
Authors in their previous work prove that any shielded cable can be treated as a travelling wave antenna while all contributing phenomena have been decomposed in order to evaluate its impact on the cable's electromagnetic radiated emissions. The proposed methodology has been validated employing monochromatic excitation over various ground planes and heights in a coaxial cable. In the present paper, authors expand this previously established methodology in more complex structures and for more complex signals; exploring the case of SpaceWire cable over an aluminium ground fed with Low Voltage Differential Signal (LVDS). This specific setup is studied due to its crucial role in current Space missions and applications, as it is the standard for harness and grounding design. SpaceWire is a space-application focused cable with four shielded twisted pairs employing LVDS signaling, a geometry requiring rather cumbersome calculations in order to analytically extract the radiated emissions. Authors claim that this issue can be bypassed based on the aforementioned methodology identifying the current distribution on the shield responsible for the radiation with the aid of the Differential Evolution algorithm. Results showcase that the extracted model can accurately describe the phenomenon.
Christos Nikolopoulos; Anargyros Baklezos; Christos N. Capsalis. A Novel Approach to Radiated Emissions Modeling of Low Voltage Differential Signal on SpaceWire Cable Employing Differential Evolution. 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) 2019, 1929 -1936.
AMA StyleChristos Nikolopoulos, Anargyros Baklezos, Christos N. Capsalis. A Novel Approach to Radiated Emissions Modeling of Low Voltage Differential Signal on SpaceWire Cable Employing Differential Evolution. 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring). 2019; ():1929-1936.
Chicago/Turabian StyleChristos Nikolopoulos; Anargyros Baklezos; Christos N. Capsalis. 2019. "A Novel Approach to Radiated Emissions Modeling of Low Voltage Differential Signal on SpaceWire Cable Employing Differential Evolution." 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) , no. : 1929-1936.
In their previous work, authors have proposed a methodology for predicting and modelling electromagnetic emissions in case of shielded coaxial cable with respect to the ground dielectric properties. In that work, a shielded coaxial cable was treated as a travelling wave antenna and the decomposed contribution of each phenomenon was validated through extensive electric field measurements of the cable over various ground planes and heights. In the present paper, authors attempt to verify the applicability of this methodology in more complex structures; exploring the case of SpaceWire cable over a CFRP ground. This setup is of major interest for Space applications, as it becomes the standard harness and grounding design for the majority of space missions. SpaceWire is a space-application focused cable with four shielded twisted pairs employing LVDS signaling, a geometry requiring rather cumbersome calculations in order to analytically extract the radiated emissions. Authors showcase that this issue can be bypassed with the proposed methodology, while measurements verify the validity of this claim also for the case of complex structures.
Christos D. Nikolopoulos; Anargyros T. Baklezos; Stylianos Tsatalas; Christos N. Capsalis. Verification of Radiated Emissions Modeling for SpaceWire/LVDS Links Routed on CFRP Ground. IEEE Transactions on Aerospace and Electronic Systems 2019, 56, 393 -402.
AMA StyleChristos D. Nikolopoulos, Anargyros T. Baklezos, Stylianos Tsatalas, Christos N. Capsalis. Verification of Radiated Emissions Modeling for SpaceWire/LVDS Links Routed on CFRP Ground. IEEE Transactions on Aerospace and Electronic Systems. 2019; 56 (1):393-402.
Chicago/Turabian StyleChristos D. Nikolopoulos; Anargyros T. Baklezos; Stylianos Tsatalas; Christos N. Capsalis. 2019. "Verification of Radiated Emissions Modeling for SpaceWire/LVDS Links Routed on CFRP Ground." IEEE Transactions on Aerospace and Electronic Systems 56, no. 1: 393-402.
Most of the space missions carry measuring instruments that are sensitive to electric fields and require strict electromagnetic cleanliness. Therefore the variations of electric fields from platform equipment have to be correctly characterized, measured and modelled. The standard measurement procedure for ELF electric field (below 250 KHz) is according to MIL-STD-461-G, where a single measurement at 1 m distance is acquired usually with a monopole antenna. Since this measurement is in the near field region, no polarization information is available and the field spectral and spatial dependency is very hard to be estimated with a single acquisition of radiated emissions. Authors in this work are proposing a measurement setup, without deviating from the MIL-STD-461-G, capable to provide adequate information in order to estimate the electric field distribution when employing equivalent dipole modelling for accurate source identification. Moreover, authors propose an approach to measure transient states of the equipment in order to be analysed and modelled.
Christos Nikolopoulos; Anargyros Baklezos; Christos N. Capsalis. Measuring Transient and Steady State Electric Field Emissions of Space Equipment for EMC and Cleanliness Purposes. 2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE) 2018, 1 -4.
AMA StyleChristos Nikolopoulos, Anargyros Baklezos, Christos N. Capsalis. Measuring Transient and Steady State Electric Field Emissions of Space Equipment for EMC and Cleanliness Purposes. 2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE). 2018; ():1-4.
Chicago/Turabian StyleChristos Nikolopoulos; Anargyros Baklezos; Christos N. Capsalis. 2018. "Measuring Transient and Steady State Electric Field Emissions of Space Equipment for EMC and Cleanliness Purposes." 2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE) , no. : 1-4.
The development of contemporary complex technological systems prerequisites interdisciplinary design and simulation methodologies. Such an approach is demonstrated in the present work. Toward manufacturing a hand-held device aiming at internal body temperature measurements using passive microwave radiometer technology, five design and simulation perspectives are elaborated. The proposed system consists of an ultra-wide-band microwave compact antenna, a multi-frequency microwave radiometer, and a digital processing unit, all enclosed in a portable arrangement. A modeling and visualization software, processes acquired measurements according to a predefined model of human breast. The system's concept of operation is based on the fact that a malignant tumor turns out to local temperature increase inside the tissue. By measuring this temperature in successive depths, using different frequency bands in the region of 1-4 GHz, as well as in nearby spatially arranged spots on the human tissue surface, 2-D and 3-D imaging of the temperature distribution are realized. This paper focuses on design and simulation approaches of all system's aspects.
Nikolaos-Antonios Livanos; Sami Hammal; Christos D. Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis; Grigorios E. Koulouras; Panagiotis I. Charamis; Ioannis O. Vardiambasis; Athanasios Nassiopoulos; Spiros A. Kostopoulos; Pantelis A. Asvestas; Dionisis A. Cavouras; Elias Siores. Design and Interdisciplinary Simulations of a Hand-Held Device for Internal-Body Temperature Sensing Using Microwave Radiometry. IEEE Sensors Journal 2018, 18, 2421 -2433.
AMA StyleNikolaos-Antonios Livanos, Sami Hammal, Christos D. Nikolopoulos, Anargyros T. Baklezos, Christos N. Capsalis, Grigorios E. Koulouras, Panagiotis I. Charamis, Ioannis O. Vardiambasis, Athanasios Nassiopoulos, Spiros A. Kostopoulos, Pantelis A. Asvestas, Dionisis A. Cavouras, Elias Siores. Design and Interdisciplinary Simulations of a Hand-Held Device for Internal-Body Temperature Sensing Using Microwave Radiometry. IEEE Sensors Journal. 2018; 18 (6):2421-2433.
Chicago/Turabian StyleNikolaos-Antonios Livanos; Sami Hammal; Christos D. Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis; Grigorios E. Koulouras; Panagiotis I. Charamis; Ioannis O. Vardiambasis; Athanasios Nassiopoulos; Spiros A. Kostopoulos; Pantelis A. Asvestas; Dionisis A. Cavouras; Elias Siores. 2018. "Design and Interdisciplinary Simulations of a Hand-Held Device for Internal-Body Temperature Sensing Using Microwave Radiometry." IEEE Sensors Journal 18, no. 6: 2421-2433.
This chapter focuses on understanding the behavior of the extremely low frequency (ELF) electric field emissions of EUTs from spacecraft subsystems and on reviewing reliable equivalent models combining measurement techniques in order to acquire a complete system electromagnetic cleanliness. More precise time variations of the electric fields produced by spacecraft equipment have to be characterized, measured, and modeled. The proposed methodology is employing equivalent dipole modeling (EDM) to describe the ELF electric field spectral dependency. Each spectral component of the measured field is considered isolated and produced by one electric dipole. In order to validate the accuracy of the proposed methodology, various ELF signals in different distances are studied. In addition, since the validation of the proposed methodology would require “on ground” measurements and due to the low-frequency range, test facilities decoupling techniques are discussed. Moreover, early considerations including contributing phenomena for the complete spacecraft system modeling are reviewed.
Christos Nikolopoulos. Extremely Low Frequency Electric Field Emissions for Space Applications. Advances in Computer and Electrical Engineering 2018, 1 -37.
AMA StyleChristos Nikolopoulos. Extremely Low Frequency Electric Field Emissions for Space Applications. Advances in Computer and Electrical Engineering. 2018; ():1-37.
Chicago/Turabian StyleChristos Nikolopoulos. 2018. "Extremely Low Frequency Electric Field Emissions for Space Applications." Advances in Computer and Electrical Engineering , no. : 1-37.
Prediction of the electric emissions in space missions is critical due to the sensitivity of their payload. A reliable method to predict such emissions is the accurate electric source identification. In this work, every space component is modeled by a small number of electric dipoles based on the measurement of the magnitude of the electric field at novel set of near-field positions. The location and electric moment are accurately predicted via stochastic algorithms resulting in the correct reconstruction of the source’s electric field both at measurement and extrapolation points.
Anargyros T. Baklezos; Christos D. Nikolopoulos; Christos N. Capsalis. An equivalent dipole method with novel measurement positioning for modeling electric emissions in space missions. Electromagnetics 2017, 37, 439 -453.
AMA StyleAnargyros T. Baklezos, Christos D. Nikolopoulos, Christos N. Capsalis. An equivalent dipole method with novel measurement positioning for modeling electric emissions in space missions. Electromagnetics. 2017; 37 (7):439-453.
Chicago/Turabian StyleAnargyros T. Baklezos; Christos D. Nikolopoulos; Christos N. Capsalis. 2017. "An equivalent dipole method with novel measurement positioning for modeling electric emissions in space missions." Electromagnetics 37, no. 7: 439-453.
The majority of the space missions carry measuring instruments that are sensitive to electric fields and require stringent electromagnetic cleanliness. Therefore, the time variations of electric fields produced from spacecraft equipment have to be characterized, measured, and modeled. In this paper, a novel methodology is proposed, employing equivalent dipole modeling to describe the extremely low frequency (ELF) electric field spectral dependence. Each spectral component of the measured field is considered isolated and produced by one electric dipole. An iteration of this process over the whole frequency range yields the complete ELF model of the equipment under test, which consists of one electric dipole per frequency. In order to validate the accuracy of the proposed methodology, various ELF signals in different distances are studied.
Grigorios I. Koutantos; Christos Nikolopoulos; Anargyros Baklezos; Christos N. Capsalis. On the Modeling of ELF Electric Fields for Space Mission Equipment. IEEE Transactions on Electromagnetic Compatibility 2017, 59, 1457 -1464.
AMA StyleGrigorios I. Koutantos, Christos Nikolopoulos, Anargyros Baklezos, Christos N. Capsalis. On the Modeling of ELF Electric Fields for Space Mission Equipment. IEEE Transactions on Electromagnetic Compatibility. 2017; 59 (5):1457-1464.
Chicago/Turabian StyleGrigorios I. Koutantos; Christos Nikolopoulos; Anargyros Baklezos; Christos N. Capsalis. 2017. "On the Modeling of ELF Electric Fields for Space Mission Equipment." IEEE Transactions on Electromagnetic Compatibility 59, no. 5: 1457-1464.
Link speed and code word length in spacecraft digital systems have a critical effect on equipment design in terms of operation and electromagnetic interference. In this work the behavior of a Low Voltage Differential Signaling / Spacewire link is evaluated through radiated as well as signal spectrum measurements. Various pulse frequencies and pattern lengths were tested and the results indicate that higher pulse frequencies increase the radiated emissions of the system. Radiated emissions are also affected by pattern length, due to the fact that the magnitude and the spacing of the spectral lines vary as the code word length increases.
Anargyros T. Baklezos; Christos Nikolopoulos; Christos N. Capsalis; Stylianos Tsatalas. Effect of LVDS link speed and pattern length on spectrum measurements of a Spacewire harness. 2017 International Workshop on Antenna Technology: Small Antennas, Innovative Structures, and Applications (iWAT) 2017, 38 -41.
AMA StyleAnargyros T. Baklezos, Christos Nikolopoulos, Christos N. Capsalis, Stylianos Tsatalas. Effect of LVDS link speed and pattern length on spectrum measurements of a Spacewire harness. 2017 International Workshop on Antenna Technology: Small Antennas, Innovative Structures, and Applications (iWAT). 2017; ():38-41.
Chicago/Turabian StyleAnargyros T. Baklezos; Christos Nikolopoulos; Christos N. Capsalis; Stylianos Tsatalas. 2017. "Effect of LVDS link speed and pattern length on spectrum measurements of a Spacewire harness." 2017 International Workshop on Antenna Technology: Small Antennas, Innovative Structures, and Applications (iWAT) , no. : 38-41.
Satellites and spacecraft subsystems in general are vulnerable in terms of electromagnetic interference. Shielded cables, connecting these subsystems as well as the subsystems themselves, are major sources of electromagnetic (EM) emission. The minimization of these emissions is critical in order to achieve EM cleanliness. An accurate model predicting these emissions could offer great insight and enable interference minimization. In this study, a shielded cable model for predicting EM emission via decomposition of contributing phenomena is presented including the ground dielectric properties. The model is built based on a standardized measurement setup and validated for different cases of ground material and cable's position.
Anargyros Baklezos; Christos Nikolopoulos; Adrianos Katsouris; Grigoris I. Koutantos; Christos N. Capsalis. Electromagnetic Emission Modeling in Case of Shielded Cabling With Respect to the Ground Dielectric Properties. IEEE Transactions on Electromagnetic Compatibility 2016, 58, 1694 -1700.
AMA StyleAnargyros Baklezos, Christos Nikolopoulos, Adrianos Katsouris, Grigoris I. Koutantos, Christos N. Capsalis. Electromagnetic Emission Modeling in Case of Shielded Cabling With Respect to the Ground Dielectric Properties. IEEE Transactions on Electromagnetic Compatibility. 2016; 58 (6):1694-1700.
Chicago/Turabian StyleAnargyros Baklezos; Christos Nikolopoulos; Adrianos Katsouris; Grigoris I. Koutantos; Christos N. Capsalis. 2016. "Electromagnetic Emission Modeling in Case of Shielded Cabling With Respect to the Ground Dielectric Properties." IEEE Transactions on Electromagnetic Compatibility 58, no. 6: 1694-1700.
This article describes a reconfigurable monopole liquid antenna array, suitable for wireless communications in the UHF band, focusing on obtaining and controlling notch radiation directions. Two different implementations are being studied, at the beginning three collinear monopoles placed over a ground plane and then, five monopoles over a ground plane placed in such a manner as to form a cross. By replacing the parasitic elements with cylinders filled with conductive fluids and also surrounding the driven element, it is possible it is possible to change at will the whole antenna's layout and to control both the maximum directivity angle over the azimuth and the resonant frequency, filtering interfered channels and background noise. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1782–1786, 2016
Adrianos G. Katsouris; Christos Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis. A novel reconfigurable antenna array with controllable tuning and beam steering. Microwave and Optical Technology Letters 2016, 58, 1782 -1786.
AMA StyleAdrianos G. Katsouris, Christos Nikolopoulos, Anargyros T. Baklezos, Christos N. Capsalis. A novel reconfigurable antenna array with controllable tuning and beam steering. Microwave and Optical Technology Letters. 2016; 58 (8):1782-1786.
Chicago/Turabian StyleAdrianos G. Katsouris; Christos Nikolopoulos; Anargyros T. Baklezos; Christos N. Capsalis. 2016. "A novel reconfigurable antenna array with controllable tuning and beam steering." Microwave and Optical Technology Letters 58, no. 8: 1782-1786.