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  • 1.
    Asan, Noor Badariah
    et al.
    Ångström Laboratory, Microwaves in Medical Engineering Group, Department of Electrical Engineering, Uppsala University, Uppsala, Sweden; Centre for Telecommunication Research and Innovation (CeTRI), Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer, Universiti Teknikal Malaysia Melaka, Durian Tunggal, Malaysia.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt; Hannover Centre for Optical Technologies, Cluster of Excellence PhoenixD, Leibniz University Hannover, Hanover, Germany; Faculty of Mechanical Engineering, Institute of Transport and Automation Technology, Leibniz University Hannover, Garbsen, Germany.
    Perez, Mauricio D.
    Ångström Laboratory, Microwaves in Medical Engineering Group, Department of Electrical Engineering, Uppsala University, Uppsala, Sweden.
    Joseph, Laya
    Ångström Laboratory, Microwaves in Medical Engineering Group, Department of Electrical Engineering, Uppsala University, Uppsala, Sweden.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Voigt, Thiemo
    Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Augustine, Robin
    Ångström Laboratory, Microwaves in Medical Engineering Group, Department of Electrical Engineering, Uppsala University, Uppsala, Sweden.
    Fat-IntraBody Communication at 5.8 GHz: Verification of Dynamic Body Movement Effects using Computer Simulation and Experiments2021Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 9, s. 48429-48445Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents numerical modeling and experimental validation of the signal path loss at the 5.8 GHz Industrial, Scientific, and Medical (ISM) band, performed in the context of fat-intrabody communication (fat-IBC), a novel intrabody communication platform using the body-omnipresent fat tissue as the key wave-guiding medium. Such work extends our previous works at 2.0 and 2.4 GHz in the characterization of its performance in other useful frequency range. In addition, this paper also includes studies of both static and dynamic human body movements. In order to provide with a more comprehensive characterization of the communication performance at this frequency, this work focuses on investigating the path loss at different configurations of fat tissue thickness, antenna polarizations, and locations in the fat channel. We bring more realism to the experimental validation by using excised tissues from porcine cadaver as both their fat and muscle tissues have electromagnetic characteristics similar to those of human with respect to current state-of-art artificial phantom models. Moreover, for favorable signal excitation and reception in the fat-IBC model, we used topology optimized waveguide probes. These probes provide an almost flat response in the frequency range from 3.2 to 7.1 GHz which is higher than previous probes and improve the evaluation of the performance of the fat-IBC model. We also discuss various aspects of real-world scenarios by examining different models, particularly homogeneous multilayered skin, fat, and muscle tissue. To study the effect of dynamic body movements, we examine the impact of misalignment, both in space and in wave polarization, between implanted nodes. We show in particular that the use of fat-IBC techniques can be extended up in frequency to a broadband channel at 5.8 GHz.

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  • 2. Asan, Noor Badariah
    et al.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Perez, Mauricio David
    Shah, Syaiful Redzwan Mohd
    Velander, Jacob
    Blokhuis, Taco J.
    Voigt, Thiemo
    Augustine, Robin
    Assessment of Blood Vessel Effect on Fat-Intrabody Communication Using Numerical and Ex-Vivo Models at 2.45 GHZ2019Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 89886-89900Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential offered by the intra-body communication (IBC) over the past few years has resulted in a spike of interest for the topic, specifically for medical applications. Fat-IBC is subsequently a novel alternative technique that utilizes fat tissue as a communication channel. This work aimed to identify such transmission medium and its performance in varying blood-vessel systems at 2.45 GHz, particularly in the context of the IBC and medical applications. It incorporated three-dimensional (3D) electromagnetic simulations and laboratory investigations that implemented models of blood vessels of varying orientations, sizes, and positions. Such investigations were undertaken by using ex-vivo porcine tissues and three blood-vessel system configurations. These configurations represent extreme cases of real-life scenarios that sufficiently elucidated their principal influence on the transmission. The blood-vessel models consisted of ex-vivo muscle tissues and copper rods. The results showed that the blood vessels crossing the channel vertically contributed to 5.1 dB and 17.1 dB signal losses for muscle and copper rods, respectively, which is the worst-case scenario in the context of fat-channel with perturbance. In contrast, blood vessels aligned-longitudinally in the channel have less effect and yielded 4.5 dB and 4.2 dB signal losses for muscle and copper rods, respectively. Meanwhile, the blood vessels crossing the channel horizontally displayed 3.4 dB and 1.9 dB signal losses for muscle and copper rods, respectively, which were the smallest losses among the configurations. The laboratory investigations were in agreement with the simulations. Thus, this work substantiated the fat-IBC signal transmission variability in the context of varying blood vessel configurations.

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  • 3. Asan, Noor Badariah
    et al.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Redzwan, Syaiful
    Velander, Jacob
    Voigt, Thiemo
    Augustine, Robin
    Impact of Blood Vessels on Data Packet Transmission Through the Fat Channel2018Ingår i: 2018 IEEE INTERNATIONAL RF AND MICROWAVE CONFERENCE (RFM 2018) / [ed] Pasya, I Awang, AH Seman, FC, IEEE conference proceedings, 2018, s. 196-198Konferensbidrag (Refereegranskat)
    Abstract [en]

    The reliability of intra-body wireless communication systems is very important in medical applications to ensure the data transmission between implanted devices. In this paper, we present newly developed measurements to investigate the effect of blood vessels on the data packet reception through the fat tissue. We use an IEEE 802.15.4-based WBAN prototype to measure the packet reception rate (PRR) through a tissue-equivalent phantom model. The blood vessels are modelled using copper rods. We measure the PRR at the frequency 2.45 GHz for several power levels. The results revealed that the presence of blood vessels aligned with the fat channel has tiny influence on the PRR when measured over the range -25 dBm to 0 dBm power level and for different blood vessels positions. Our investigations show 97% successful PRR through a 10 cm length fat channel in presence of the blood vessels.

  • 4. Asan, Noor Badariah
    et al.
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Shah, Syaiful Redzwan Mohd
    Rydberg, Anders
    Blokhuis, Taco J.
    Carlsson, Per-Ola
    Voigt, Thiemo
    Augustine, Robin
    Intra-body microwave communication through adipose tissue2017Ingår i: Healthcare technology letters, E-ISSN 2053-3713, Vol. 4, nr 4, s. 115-121Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The human body can act as a medium for the transmission of electromagnetic waves in the wireless body sensor networks context. However, there are transmission losses in biological tissues due to the presence of water and salts. This Letter focuses on lateral intra-body microwave communication through different biological tissue layers and demonstrates the effect of the tissue thicknesses by comparing signal coupling in the channel. For this work, the authors utilise the R-band frequencies since it overlaps the industrial, scientific and medical radio (ISM) band. The channel model in human tissues is proposed based on electromagnetic simulations, validated using equivalent phantom and ex-vivo measurements. The phantom and ex-vivo measurements are compared with simulation modelling. The results show that electromagnetic communication is feasible in the adipose tissue layer with a low attenuation of approximate to 2 dB per 20 mm for phantom measurements and 4 dB per 20 mm for ex-vivo measurements at 2 GHz. Since the dielectric losses of human adipose tissues are almost half of ex-vivo tissue, an attenuation of around 3 dB per 20 mm is expected. The results show that human adipose tissue can be used as an intra-body communication channel.

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  • 5. Asan, Noor Badariah
    et al.
    Penichet, Carlos Perez
    Shah, Syaiful Redzwan Mohd
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, 32952, Egypt.
    Rydberg, Anders
    Blokhuis, Taco J.
    Voigt, Thiemo
    Augustine, Robin
    Data Packet Transmission Through Fat Tissue for Wireless IntraBody Networks2017Ingår i: IEEE Journal of Electromagnetics, RF and Microwaves in Medicine and Biology, ISSN 2469-7249, Vol. 1, nr 2, s. 43-51Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper explores high data rate microwave communication through fat tissue in order to address the wide bandwidth requirements of intrabody area networks. We have designed and carried out experiments on an IEEE 802.15.4-based WBAN prototype by measuring the performance of the fat tissue channel in terms of data packet reception with respect to tissue length and power transmission. This paper proposes and demonstrates a high data rate communication channel through fat tissue using phantom and ex-vivo environments. Here, we achieve a data packet reception of approximately 96% in both environments. The results also show that the received signal strength drops by similar to 1 dBm per 10 mm in phantom and similar to 2 dBmper 10 mm in ex-vivo. The phantom and ex-vivo experimentations validated our approach for high data rate communication through fat tissue for intrabody network applications. The proposed method opens up new opportunities for further research in fat channel communication. This study will contribute to the successful development of high bandwidth wireless intrabody networks that support high data rate implanted, ingested, injected, or worn devices.

  • 6. Asan, Noor Badariah
    et al.
    Redzwan, Syaiful
    Rydberg, Anders
    Augustine, Robin
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Voigt, Thiemo
    Human Fat Tissue: A Microwave Communication Channel2017Ingår i: 2017 First IEEE MTT-S International Microwave Bio Conference (IMBIOC), IEEE, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present an approach for communication through human body tissue in the R-band frequency range. This study examines the ranges of microwave frequencies suitable for intra-body communication. The human body tissues are characterized with respect to their transmission properties using simulation modeling and phantom measurements. The variations in signal coupling with respect to different tissue thicknesses are studied. The simulation and phantom measurement results show that electromagnetic communication in the fat layer is viable with attenuation of approximately 2 dB per 20 mm.

  • 7. Asan, Noor Badariah
    et al.
    Redzwan, Syaiful
    Velander, Jacob
    Perez, Mauricio D.
    Augustine, Robin
    Voigt, Thiemo
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications,Menoufia University, Menouf, Egypt.
    Blokhuis, Taco J.
    Effects of Blood Vessels on Fat Channel Microwave Communication2018Ingår i: 2018 IEEE Conference on Antenna Measurements & Applications (CAMA), IEEE, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    This study aims to investigate the reliability of intra-body microwave propagation through the fat tissue in presence of blood vessels. Here, we consider three types of blood vessels with different sizes. We investigate the impact of the number of blood vessels and their alignment on the transmission of microwave signals through the fat channel. In our study, we employ two probes that act as a transmitter and a receiver. The probes are designed to operate at the Industrial, Scientific, and Medical radio band (2.45 GHz). For a channel length of 100 mm, our results indicate that the presence of the blood vessels may increase the channel path loss by similar to 1.5 dB and similar to 4.5 dB when the vessels are aligned and orthogonally aligned with the fat channel, respectively.

  • 8. Asan, Noor Badariah
    et al.
    Velander, Jacob
    Redzwan, Syaiful
    Augustine, Robin
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Voigt, Thiemo
    Blokhuis, Taco J.
    Reliability of the Fat Tissue Channel for Intra-body Microwave Communication2017Ingår i: 2017 IEEE Conference on Antenna Measurements & Applications (CAMA), IEEE , 2017, s. 310-313Konferensbidrag (Refereegranskat)
    Abstract [en]

    Recently, the human fat tissue has been proposed as a microwave channel for intra-body sensor applications. In this work, we assess how disturbances can prevent reliable microwave propagation through the fat channel. Perturbants of different sizes are considered. The simulation and experimental results show that efficient communication through the fat channel is possible even in the presence of perturbants such as embedded muscle layers and blood vessels. We show that the communication channel is not affected by perturbants that are smaller than 15 mm cube.

  • 9. Asan, Noor Badariah
    et al.
    Velander, Jacob
    Redzwan, Syaiful
    Perez, Mauricio D.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Blokhuis, Taco J.
    Voigt, Thiemo
    Augustine, Robin
    Effect of Thickness Inhomogeneity in Fat Tissue on In-Body Microwave Propagation2018Ingår i: Proceedings of the 2018 IEEE/MTT-S International Microwave Biomedical Conference (IMBIOC), IEEE, 2018, s. 136-138Konferensbidrag (Refereegranskat)
    Abstract [en]

    In recent studies, it has been found that fat tissue can be used as a microwave communication channel. In this article, the effect of thickness inhomogeneities in fat tissues on the performance of in-body microwave communication at 2.45 GHz is investigated using phantom models. We considered two models namely concave and convex geometrical fat distribution to account for the thickness inhomogeneities. The thickness of the fat tissue is varied from 5 mm to 45 mm and the Gap between the transmitter/receiver and the starting and ending of concavity/convexity is varied from 0 mm to 25 mm for a length of 100 mm to study the behavior in the microwave propagation. The phantoms of different geometries, concave and convex, are used in this work to validate the numerical studies. It was noticed that the convex model exhibited higher signal coupling by an amount of 1 dB (simulation) and 2 dB (measurement) compared to the concave model. From the study, it was observed that the signal transmission improves up to 30 mm thick fat and reaches a plateau when the thickness is increased further.

  • 10. Badariah Asan, Noor
    et al.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Velander, Jacob
    Redzwan Mohd Shah, Syaiful
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Blokhuis, Taco J.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Voigt, Thiemo
    Augustine, Robin
    Characterization of the Fat Channel for Intra-Body Communication at R-Band Frequencies2018Ingår i: Sensors, E-ISSN 1424-8220, Vol. 18, nr 9, artikel-id 2752Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7–2.6 GHz). The proposed fat channel is based on an anatomical model of the human body. We propose a novel probe that is optimized to efficiently radiate the R-band frequencies into the fat tissue. We use our probe to evaluate the path loss of the fat channel by studying the channel transmission coefficient over the R-band frequencies. We conduct extensive simulation studies and validate our results by experimentation on phantom and ex-vivo porcine tissue, with good agreement between simulations and experiments. We demonstrate a performance comparison between the fat channel and similar waveguide structures. Our characterization of the fat channel reveals propagation path loss of ∼0.7 dB and ∼1.9 dB per cm for phantom and ex-vivo porcine tissue, respectively. These results demonstrate that fat tissue can be used as a communication channel for high data rate intra-body networks.

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  • 11.
    Bokhari, Ahmad Hasnain
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Mathematics and Computer Science, Karlstad University, Karlstad, Sweden.
    Topology optimization of microwave frequency dividing multiplexers2023Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 66, artikel-id 106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We use material-distribution-based topology optimization to design a three-port frequency dividing multiplexer at microwave frequencies. That is, by placing a good electric conductor inside the design domain, we aim to design a passive device that splits the incoming signal's frequencies into two frequency bands and transmits them to their respective output ports. The Helmholtz equation is used to model the time-harmonic wave propagation problem. We use the finite element method to solve the governing equation. The adjoint variable method provides the required gradients, and we solve the topology optimization problem using Svanberg's MMA algorithm. In this study, we present a technique for modeling the distribution of a good electric conductor within the design domain. In addition, we derive a power balance expression, which aids in formulating a series of three objective functions. In each successive objective function, we add more information and evaluate its impact on the results. The results show that by selecting a suitable objective function, we achieve more than 93.7 % transmission for both the frequency bands. Moreover, the numerical experiments suggest that the optimization problem is self penalized and is sensitive to the initial design.

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  • 12. Dessouky, Ahmed M.
    et al.
    Taha, Taha E.
    Dessouky, Mohamed M.
    Eltholth, Ashraf A.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communication Engineering, Faculty of Electronic Engineering, Menoufia University, Menouf, Egypt.
    Abd El-Samie, Fathi E.
    Non-parametric spectral estimation techniques for DNA sequence analysis and exon region prediction2019Ingår i: Computers & electrical engineering, ISSN 0045-7906, E-ISSN 1879-0755, Vol. 73, s. 334-348Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioinformatics is the analysis of biological information using computers and statistical techniques. This paper presents non-parametric spectral estimation techniques based on the Discrete Fourier Transform (DFT) for the analysis of deoxyribonucleic acid (DNA) sequences. These techniques are efficient frequency-domain signal representation techniques, which improve the analysis of DNA sequences and enable the extraction of some desirable information that cannot be extracted from the time-domain representation of these sequences. The adopted techniques are the periodogram, average periodogram (Bartlett), modified average periodogram (Welch), and Blackman and Tukey spectral estimation techniques. The objective of these spectral estimation techniques is to investigate the locations of exons in DNA sequences for gene prediction. A comparison study is presented in this paper between the suggested spectral estimation techniques from the exon prediction perspective. The methods presented in this paper improve the detectability of peaks representing exon regions.

  • 13. Dessouky, Ahmed M.
    et al.
    Taha, Taha E.
    Dessouky, Mohamed M.
    Eltholth, Ashraf A.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communication Engineering, Faculty of Electronic Engineering, Menoufia University, Menouf, Egypt.
    Abd El-Samie, Fathi E.
    Visual representation of DNA sequences for exon detection using non-parametric spectral estimation techniques2019Ingår i: Nucleosides, Nucleotides & Nucleic Acids, ISSN 1525-7770, E-ISSN 1532-2335, Vol. 38, nr 5, s. 321-337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a new approach for modeling of DNA sequences for the purpose of exon detection. The proposed model adopts the sum-of-sinusoids concept for the representation of DNA sequences. The objective of the modeling process is to represent the DNA sequence with few coefficients. The modeling process can be performed on the DNA signal as a whole or on a segment-by-segment basis. The created models can be used instead of the original sequences in a further spectral estimation process for exon detection. The accuracy of modeling is evaluated evaluated by using the Root Mean Square Error (RMSE) and the R-square metrics. In addition, non-parametric spectral estimation methods are used for estimating the spectral of both original and modeled DNA sequences. The results of exon detection based on original and modeled DNA sequences coincide to a great extent, which ensures the success of the proposed sum-of-sinusoids method for modeling of DNA sequences.

  • 14.
    Gedeon, Johannes
    et al.
    Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology (Faculty of Mechanical Engineering), and Cluster of Excellence PhoenixD, Leibniz University Hannover, Hannover, Germany.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Calà Lesina, Antonio
    Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology (Faculty of Mechanical Engineering), and Cluster of Excellence PhoenixD, Leibniz University Hannover, Hannover, Germany.
    Time-domain topology optimization of arbitrary dispersive materials for broadband 3D nanophotonics inverse design2023Ingår i: ACS Photonics, E-ISSN 2330-4022, Vol. 10, nr 11, s. 3875-3887Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the last decades, nanostructures have unlocked myriads of functionalities in nanophotonics by engineering light–matter interaction beyond what is possible with conventional bulk optics. The space of parameters available for design is practically unlimited due to the large variety of optical materials and nanofabrication techniques. Thus, computational approaches are necessary to efficiently search for the optimal solutions. In this paper, we enable the free-form inverse design in 3D of linear optical materials with arbitrary dispersion and anisotropy. This is achieved by (1) deriving an analytical adjoint scheme based on the complex-conjugate pole-residue pair model in the time domain and (2) its implementation in a parallel finite-difference time-domain framework with a topology optimization routine, efficiently running on high-performance computing systems. Our method is tested on the design problem of field confinement using dispersive nanostructures. The obtained designs satisfy the fundamental curiosity of how free-form metallic and dielectric nanostructures perform when optimized in 3D, also in comparison to fabrication-constrained designs. Unconventional free-form designs revealed by computational methods, although may be challenging or unfeasible to realize with current technology, bring new insights into how light can more efficiently interact with nanostructures and provide new ideas for forward design.

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  • 15.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Metallic antenna design based on topology optimization techniques2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
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    Metallic antenna design based on topology optimization techniques
  • 16.
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Topology optimization of antennas and waveguide transitions2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis introduces a topology optimization approach to design, from scratch, efficient microwave devices, such as antennas and waveguide transitions. The design of these devices is formulated as a general optimization problem that aims to build the whole layout of the device in order to extremize a chosen objective function. The objective function quantifies some required performance and is evaluated using numerical solutions to the 3D~Maxwell's equations by the finite-difference time-domain (FDTD) method. The design variables are the local conductivity at each Yee~edge in a given design domain, and a gradient-based optimization method is used to solve the optimization problem. In all design problems, objective function gradients are computed based on solutions to adjoint-field problems, which are also FDTD discretization of Maxwell's equations but solved with different source excitations. For any number of design variables, the computation of the objective function gradient requires one solution to the original field problem and one solution to the associated adjoint-field problem. The optimization problem is solved iteratively using the globally convergent Method of Moving Asymptotes (GCMMA).

    By the proposed approach, various design problems, including tens of thousands of design variables, are formulated and solved in a few hundred iterations. Examples of solved design problems are the design of wideband antennas, dual-band microstrip antennas, wideband directive antennas, and wideband coaxial-to-waveguide transitions. The fact that the proposed approach allows a fine-grained control over the whole layout of such devices results in novel devices with favourable performance. The optimization results are successfully verified with a commercial software package. Moreover, some devices are fabricated and their performance is successfully validated by experiments.

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    Topology Optimization of Antennas and Waveguide Transitions
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  • 17.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Scheiner, Benedict
    Institute for Electronics Engineering, Friedrich-Alexander University Erlangen-Nuremberg (FAU), 91058 Erlangen, Germany.
    Michler, Fabian
    Institute for Electronics Engineering, Friedrich-Alexander University Erlangen-Nuremberg (FAU), 91058 Erlangen, Germany.
    Weigel, Robert
    Institute for Electronics Engineering, Friedrich-Alexander University Erlangen-Nuremberg (FAU), 91058 Erlangen, Germany.
    Lurz, Fabian
    Institute for Electronics Engineering, Friedrich-Alexander University Erlangen-Nuremberg (FAU), 91058 Erlangen, Germany.
    Design of Planar Microstrip-to-Waveguide Transitions Using Topology Optimization2019Ingår i: 2019 IEEE Radio and Wireless Symposium (RWS), Orlando, USA, January 20-23, 2019, IEEE, 2019, s. -3Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents a topology optimization approach to design planar transitions between a microstrip line (MSL) and a rectangular waveguide (RWG) in the K-band. The transition comprises two sub-transitions: one from the MSL to a substrate integrated waveguide (SIW) and the second from the SIW to the RWG. Both are on the same substrate and can be manufactured with a standard printed circuit board process. This leads to a very costeffective solution compared with other approaches. A WR-42 waveguide can easily be surface mounted to the transitions using a standard flange. The transitions have been fabricated, and their measured performance shows good agreement with the simulations. The MSL-SIW transition has a broadband behavior and the SIW-RWG transition still reaches a relative bandwidth of 10%.

  • 18.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Hannover Centre for Optical Technologies, Institute of Transport and Automation Technology (Faculty of Mechanical Engineering), and Cluster of Excellence PhoenixD, Leibniz University Hannover, Hannover, Germany, Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Cala Lesina, Antonio
    Time-domain topology optimization of wideband dispersive plasmonic nanostructures2022Ingår i: 2022 Photonics North (PN): Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2022Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a time-domain topology optimization algorithm to inverse design dispersive materials based on the Drude model. The method is demonstrated on plasmonic nanostructures with wideband performance.

  • 19.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology (Faculty of Mechanical Engineering), and Cluster of Excellence PhoenixD, Leibniz University Hannover, Hannover, Germany; Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Calà Lesina, Antonio
    Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology (Faculty of Mechanical Engineering), and Cluster of Excellence PhoenixD, Leibniz University Hannover, 30167 Hannover, Germany.
    Topology optimization of dispersive plasmonic nanostructures in the time-domain2022Ingår i: Optics Express, E-ISSN 1094-4087, Vol. 30, nr 11, s. 19557-19572Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Topology optimization techniques have been applied in integrated optics and nanophotonics for the inverse design of devices with shapes that cannot be conceived by human intuition. At optical frequencies, these techniques have only been utilized to optimize nondispersive materials using frequency-domain methods. However, a time-domain formulation is more efficient to optimize materials with dispersion. We introduce such a formulation for the Drude model, which is widely used to simulate the dispersive properties of metals, conductive oxides, and conductive polymers. Our topology optimization algorithm is based on the finite-difference time-domain (FDTD) method, and we introduce a time-domain sensitivity analysis that enables the evaluation of the gradient information by using one additional FDTD simulation. The existence of dielectric and metallic structures in the design space produces plasmonic field enhancement that causes convergence issues. We employ an artificial damping approach during the optimization iterations that, by reducing the plasmonic effects, solves the convergence problem. We present several design examples of 2D and 3D plasmonic nanoantennas with optimized field localization and enhancement in frequency bands of choice. Our method has the potential to speed up the design of wideband optical nanostructures made of dispersive materials for applications in nanoplasmonics, integrated optics, ultrafast photonics, and nonlinear optics.

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  • 20.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Menoufia University, Department of Electronics and Electrical Communications, Menouf, Egypt.
    Evlynkhin, Andrey B.
    Institute of Quantum Optics, and Cluster of Excellence PhoenixD Leibniz University Hannover, Hannover, Germany.
    Lesina, Antonio Cala
    Leibniz University Hannover, Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology, and Cluster of Excellence PhoenixD, Hannover, Germany.
    On the physics and design of plasmonic anapoles in metallic nanostructures2023Ingår i: 2023 international conference on electromagnetics in advanced applications (ICEAA): proceeding, IEEE, 2023, s. 507-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nanostructures with anapole states have attracted significant interest in the field of nanophotonics due to their ability to exhibit field enhancement while providing transparency, specifically a low extinction cross-section [1, 2]. Anapoles have been observed in both dielectric [3] and plasmonic [4] nanostructures. Typically, anapole states arise from the interference between electric and toroidal dipole moments. However, even in cases where the toroidal dipole contribution is negligible due to a planar design, the presence of an anapole can still be observed.

  • 21.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Evlyukhin, Andrey B.
    Institute of Quantum Optics and Cluster of Excellence PhoenixD, Leibniz University Hannover, Hannover, Germany.
    Lesina, Antonio Calà
    Hannover Centre for Optical Technologies, Institute for Transport and Automation Technology (Faculty of Mechanical Engineering) and Cluster of Excellence PhoenixD, Leibniz University Hannover, Hannover, Germany.
    Anapole metallic nanostructures for metarsurface applications2023Ingår i: META 2023 Paris - France. The 13th International Conference on Metamaterials, Photonic Crystals and Plasmonics: Proceedings / [ed] Philippe Lalanne; Said Zouhdi, META Conference , 2023, s. 583-583Konferensbidrag (Refereegranskat)
    Abstract [en]

    Anapole states are broadly investigated in nanophotonics for their ability to provide field enhancement and transparency. While low extinction has been achieved in dielectric nanoparticles due to the absence of intrinsic losses, in the case of plasmonic nanostructures this is still elusive. In this talk, we will present recent findings on anapole states in planar plasmonic nanostructures that were optimized for near-fieldenergy enhancement using a topology optimization approach. The optimized structures exhibit an anapole state with characteristic properties in the visible regime including weak absorption, high near-field enhancement outside the structure, and strong suppression of scattering. We use our multipole analysis to explain both thenear-field and the far-field features of the anapole state possessed by the nanostructures. Because of the low inter-coupling at the anapole state, the nanostructures act as individual meta-atoms that preserve their optical response even when used in highly packed metasurfaces and metamaterials. Due to their transparency while providing field enhancement, anapoles might be combined with waveguides in integrated optical platforms to unlock advanced functionalities for sensing, nonlinear optics, and optical information processing. 

  • 22.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, 32952 Menouf, Egypt.
    Martynenko, Denys
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Fischer, Gunter
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Compact Differential-Fed Planar Filtering Antennas2019Ingår i: Electronics, E-ISSN 2079-9292, Vol. 8, nr 11, artikel-id 1241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper proposes novel low-profile differential-fed planar antennas with embedded sharp frequency selectively. The antennas are compact and easy to integrate with differential devices without matching baluns. The antenna design is formulated as a topology optimization problem, where requirements on impedance bandwidth, directivity, and filtering are used as the design objectives. The optimized antennas operate over the frequency band 6.0-8.5 GHz. The antennas have reflection coefficients below -15 dB, cross-polarization levels below -42 dB, a maximum gain of 6.0 +/- 0.5 dB, and a uniform directivity over more than 130 degrees beamwidth angle in the frequency band of interest. In addition, the antennas exhibit sharp roll-off between the operational band and frequencies around the 5.8 GHz WiFi band and the 10 GHz X-band. One antenna has been fabricated with a good match between simulation and measurement results.

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  • 23.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Augustine, Robin
    Uppsala University.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Topology optimization of planar antennas for wideband near-field coupling2015Ingår i: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 63, nr 9, s. 4208-4213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present an approach to design from scratch planar microwave antennas for the purpose of ultra-wideband (UWB) near-field sensing. Up to about 120 000 design variables associated with square grids on planar substrates are subject to design, and a numerical optimization algorithm decides, after around 200 iterations, for each edge in the grid whether it should consist of metal or a dielectric. The antenna layouts produced with this approach show UWB impedance matching properties and near-field coupling coefficients that are flat over a much wider frequency range than a standard UWB antenna. The properties of the optimized antennas are successfully cross-verified with a commercial software and, for one of the designs, also validated experimentally. We demonstrate that an antenna optimized in this way shows a high sensitivity when used for near-field detection of a phantom with dielectric properties representative of muscle tissue.

  • 24.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of electronics and electrical communications, Menoufia University, Menouf, 32952, Egypt.
    Noreland, Daniel
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Topology Optimisation of Wideband Coaxial-to-Waveguide Transitions2017Ingår i: Scientific Reports, E-ISSN 2045-2322, Vol. 7, artikel-id 45110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To maximize the matching between a coaxial cable and rectangular waveguides, we present a computational topology optimisation approach that decides for each point in a given domain whether to hold a good conductor or a good dielectric. The conductivity is determined by a gradient-based optimisation method that relies on finite-difference time-domain solutions to the 3D Maxwell’s equations. Unlike previously reported results in the literature for this kind of problems, our design algorithm can efficiently handle tens of thousands of design variables that can allow novel conceptual waveguide designs. We demonstrate the effectiveness of the approach by presenting optimised transitions with reflection coefficients lower than −15dB over more than a 60% bandwidth, both for right-angle and end-launcher configurations. The performance of the proposed transitions is crossverified with a commercial software, and one design case is validated experimentally.

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  • 25.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communication Engineering, Menoufia University.
    Scheiner, Benedict
    Michler, Fabian
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Röhrl, Franz
    Zorn, Stefan
    Weigel, Robert
    Lurz, Fabian
    Multilayer Topology Optimization of Wideband SIW-to-Waveguide Transitions2020Ingår i: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 68, nr 4, s. 1326-1339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article utilizes a topology optimization approach to design planar multilayer transitions between substrate integrated waveguides (SIWs) and rectangular waveguides (RWGs). The optimization problem is formulated based on the modal field analyses and Maxwell's equations in the time domain solved by the finite-difference time-domain (FDTD) method. We present a time-domain boundary condition based on the Klein–Gordon equation to split traveling waves at homogeneous waveguide ports. We employ the boundary condition to compute portal quantities and to devise an adjoint-field system that enabled an efficient computation of the objective function gradient. We solve design problems that include more than 105 000 design variables by using less than 400 solutions of Maxwell's equations. Moreover, a new formulation that effectively combats the development of in-band resonances in the design is presented. The transition configuration allows the direct mount of conventional RWG sections on the circuit board and aims to cover the entire K-band. The guiding structure of the optimized transition requires blind vias, which is realized by a simple and cost-efficient technique. In addition, the transition is optimized for three different setups that can be used to provide different field polarizations. The proposed transitions show less than 1-dB insertion loss and around 15-dB return loss over the frequency interval 18–28 GHz. Several prototypes are fabricated with an excellent match between the simulation and measurement results.

  • 26.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Conductive material distribution optimization for ultrawideband antennas2013Ingår i: Proceedings 11th International Conference on Mathematical and Numerical Aspects of Waves: Waves 2013, Tunis: ENIT-LAMSIN , 2013, s. 171-172Konferensbidrag (Refereegranskat)
    Abstract [en]

    An Ultrawideband (UWB) planar monopole an-tenna is designed using the material distribution ap-proach to topology optimization. The design variablesare the local conductivity values in a 75 × 75 mm areawhere the radiating element can be located. Theantenna is optimized for maximum reception, in anattached coaxial cable, of incoming plane waves. Thewave propagation is modeled using the time domain3D Maxwell equations discretized using FDTD, andthe optimization is carried out using a gradient-basedoptimization method, in which the derivatives aresupplied through solving corresponding adjoint equa-tions. The outer dimensions of the optimized antennais 75 × 60 mm, and its reflection coefficient |S11 |,with respect to a feeding signal in the coaxial cable,stays below −10 dB throughout the frequency band1.2–9.7 GHz.

  • 27.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Patch and ground plane design of microstrip antennas by material distribution topologly optimization2014Ingår i: Progress in Electromagnetics Research B, E-ISSN 1937-6472, Vol. 59, s. 89-102Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We use a gradient-based material distribution approach to design conductive parts of microstrip antennas in an efficient way. The approach is based on solutions of the 3D Maxwell's equation computed by the finite-difference time-domain (FDTD) method. Given a set of incoming waves, our objective is to maximize the received energy by determining the conductivity on each Yee-edge in the design domain. The objective function gradient is computed by the adjoint-field method. A microstrip antenna is designed to operate at 1.5 GHz with 0.3 GHz bandwidth. We present two design cases. In the first case, the radiating patch and the finite ground plane are designed in two separate phases, whereas in the second case, the radiating patch and the ground plane are simultaneously designed. We use more than 58,000 design variables and the algorithm converges in less than 150 iterations. The optimized designs have impedance bandwidths of 13% and 36% for the first and second design case, respectively.

  • 28.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Time-Domain Sensitivity Analysis for Conductivity Distribution in Maxwell's Equations2015Rapport (Övrigt vetenskapligt)
    Abstract [en]

    We present expressions for the derivatives of the outgoing signal in coaxial cables with respect to the conductivity distribution in a specific domain. The derived expressions can be used with gradient-based optimization methods to design metallic electromagnetic devices, such as antennas and waveguides. We use the adjoint-field method to derive the expressions and the derivation is based on the 3D time-domain Maxwell's equations. We present two derivative expressions; one expression is derived in the continuous case and the second is derived based on the FDTD discretization of Maxwell's equations, including the uniaxial perfectly match layer (UPML) to simulate the radiation boundary condition. The derivatives are validated through a numerical example, where derivatives computed by the adjoint-field method are compared against derivatives computed with finite differences. Up to 7 digits precision matching is obtained.

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  • 29.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Topology optimization of metallic antennas2014Ingår i: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 62, nr 5, s. 2488-2500Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce an approach to carry out layout optimization of metallic antenna parts. An optimization technique first developed for the optimization of load-bearing elastic structures is adapted for the purpose of metallic antenna design. The local conductivity values in a given region are used as design variables and are iteratively updated by a gradient-based optimization algorithm. Given a set of time-domain signals from exterior sources, the design objective is here to maximize the energy received by the antenna and transmitted to a coaxial cable. The optimization proceeds through a sequence of coarsely-defined lossy designs with successively increasing details and less losses as the iterations proceed. The objective function gradient is derived based on the FDTD discretization of Maxwell's equations and is expressed in terms of field solutions of the original antenna problem and an adjoint field problem. The same FDTD code, but with different wave sources, is used for both the original antenna problem and the adjoint problem. For any number of design variables, the gradient is evaluated on the basis of only two FDTD simulations, one for the original antenna problem and another for the adjoint field problem. We demonstrate the capability of the method by optimizing the radiating patch of both UWB monopole and microstrip antennas. The UWB monopole is designed to radiate over a wide frequency band 1-10 GHz, while the microstrip patch is designed for single and dual frequency band operation. In these examples, there are more than 20,000 design variables, and the algorithm typically converges in less than 150 iterations. The optimization results show a promising use of the proposed approach as a general method for conceptual design of near-resonance metallic antennas.

  • 30.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Topology optimization of UWB monopole antennas2013Ingår i: 7th European Conference on Antennas and Propagation (EuCAP2013), New York: IEEE conference proceedings, 2013, s. 1488-1492Konferensbidrag (Refereegranskat)
    Abstract [en]

    A Topology optimization technique is used for complete layout optimization of the radiating element of a planar monopole antenna. The design objective is to find a conductivity distribution that maximizes the energy received by the planar monopole over the frequency band 1-10 GHz. The finite difference time domain method (FDTD) is used for the numerical calculations, and an adjoint problem is derived to calculate the corresponding sensitivities. Numerical results show a promising use of topology optimization techniques for the systematic design of ultrawideband monopoles.

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  • 31.
    Hassan, Emadeldeen
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Wadbro, Eddie
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Hägg, Linus
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Berggren, Martin
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap.
    Topology optimization of compact wideband coaxial-to-waveguide transitions with minimum-size control2018Ingår i: Structural and multidisciplinary optimization (Print), ISSN 1615-147X, E-ISSN 1615-1488, Vol. 57, nr 4, s. 1765-1777Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents a density-based topology optimization approach to design compact wideband coaxial-to-waveguide transitions. The underlying optimization problem shows a strong self penalization towards binary solutions, which entails mesh-dependent designs that generally exhibit poor performance. To address the self penalization issue, we develop a filtering approach that consists of two phases. The first phase aims to relax the self penalization by using a sequence of linear filters. The second phase relies on nonlinear filters and aims to obtain binary solutions and to impose minimum-size control on the final design. We present results for optimizing compact transitions between a 50-Ohm coaxial cable and a standard WR90 waveguide operating in the X-band (8-12 GHz).

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  • 32. Heining, Simon
    et al.
    Michler, Fabian
    Scheiner, Benedict
    Hassan, Emadeldeen
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för datavetenskap. Department of Electronics and Electrical Communications, Menoufia University, Menouf, Egypt.
    Koelpin, Alexander
    Weigel, Robert
    Lurz, Fabian
    An Ultra Broadband Multi-Tone Six-Port Radar for Distance Measurements in K-Band Waveguides2020Ingår i: Proceedings of the 2020 IEEE Radio and Wireless Symposium (RWS), IEEE, 2020, s. 279-282Konferensbidrag (Refereegranskat)
    Abstract [en]

    Continuous wave (CW) radars show an excellent performance in high precision distance measurements. However, when it comes to absolute distances, the ambiguity of these systems is a notable issue. To extend the unambigous range beyond λ/2, dual tone systems have been presented using two spaced CW measurements. In this paper, a broadband multi-tone radar operating in the K-band using six-port technology is presented. By using more than two frequencies, the unambigous range can be further enlarged. The radar system presented in this paper is able to perform 5-FSK measurements within a bandwidth of 5.5GHz delivering an update rate of 25Hz and a precision of 37.96µm.

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