Topic outline

  • This research seminar features both presentations by invited speakers from outside Aalto, as well as researchers from the Department of Electronics and Nanoengineering. The regular time-slot is Wednesday morning 10:15 - 11:45, but there are exceptions, depending e.g. on the availability of external speakers. The seminar will be in TU3 at the 1st floor of TUAS building (Maarintie 8, Otaniemi, Espoo), if not otherwise stated in the program.

    There is no formal enrollment needed, anyone can attend the seminar anytime. For students who wish to get credits from their seminar attendance, please, simply mark your name on the attendance sheet that is circulated in each session. After 13 attended seminar sessions you are entitled to 1 credit point, and you may repeat this and earn another credit point as many times as you like. Contact Zachary Taylor (name.family name@aalto.fi) or Sergei Tretyakov (name.family name@aalto.fi) about your credits.


    ELE seminar Spring 2021

      




    Wednesday TBD, at 10:15, on Zoom
    Prof Elliott Brown, Wright State University (USA)
    Title: TBD
    Abstract: TBD


    Wednesday TBD, at 10:15, on Zoom
    Prof. Caterina Soldano, Aalto University (Finland)
    Title: TBD
    Abstract: TBD


    -------------------------------------------

    ARCHIVE


    Wednesday 05.05, at 10:15, on Zoom
    Speaker: Prof Zachary Taylor, Aalto University (Finland)
    Title: Bacterial biofilm disruption with laser generated shockwaves
    Abstract: Persistent, antibiotic resistant, bacterial biofilm infections are a growing hinderance to wound closure and wound healing. Typical treatments including debridement and topical medication can reduce biofilm burden but have demonstrated poor efficacy in attacking the underlying infections. In this talk we discuss a novel treatment based on laser generated shockwave. Metallic films on flexible substrates are ablated with a high energy Q-swtiched, ND:YAG laser and the mechanical shockwave, generated by the fast thermal expansion possesses therapeutic properties that are impossible to mimic with standard ultrasonic techniques.



    Wednesday 21.04, at 10:15, on Zoom

    Speaker: Dr. Juho Pokki, Aalto University (Finland)

    Title: Measuring cell-affecting mechanical cues for quantifying progression of breast cancer

    Abstract: Breast-cancer progression typically involves stiffening of the tumor microenvironment, and the increased stiffness is shown to promote malignancy. However, cells also remodel the microenvironment they interact with, dynamically changing the biomechanics they respond to. This talk will present microscope-integrated systems that measure (1) how biomechanics varies within simulated tumor microenvironments, (2) how cells remodel their microenvironment’s  biomechanics and structure, and (3) which force levels cancer cells exert during invasive migration. In the future, systems quantifying cell-affecting biomechanics could provide earlier, more accurate diagnoses of breast cancer, and personalized drug-efficacy screening.

    Zoom link: https://aalto.zoom.us/j/67317474207



    Wednesday 24.03, at 10:15, on Zoom
    Prof. Helena Rodilla Chalmers University (Sweden)
    Title: Exploring life science with terahertz electronics.
    Abstract: In the last years I have focused my research interest in exploring the potential of terahertz technology in life science. In this talk, I will present my journey into this field, with special focus in probing molecular structure and dynamics, lab-on-a-chip sensing and pharmaceutical products inspection. I will introduce the potential, challenges and limitations, and describe the main results obtained along this journey.




    Wednesday 31.03, at 10:15, on Zoom
    Prof. Emma MacPherson, University of Warwick (UK)
    Title: TBD
    Abstract: TBD




    Wednesday 17.03, at 10:15, on Zoom
    Dr. Mikko Varonen, VTT (Finland)
    Title: MMIC design – from 5G RF front-ends to cryogenic receivers for radio astronomy
    Abstract: The enormous development in monolithic microwave integrated circuit technology (MMIC) in the past decade have enabled the holistic design of millimeter-wave systems for both commercial purposes and applications with fundamental and applied scientific goals. This presentation will give an update of current trends in millimeter-wave integrated circuit development. We will review the pros and cons of different MMIC technologies and examine their usability through example applications ranging from complex silicon based phased-arrays for 5G telecommunications to cryogenic hybrid InP/SiGe receivers for radio astronomy.


    Thursday 11.03, at 10:15, on Zoom

    Author:  Joel Lamberg

    Title: Electromagnetic beam synthesis from spherical surface electric field distributions using modified Fourier optics method

    Supervisor: Prof. Zachary Taylor

    Advisor:  D.Sc. (Tech) Aleksi Tamminen

    Abstract: Conventional methods for evaluating electromagnetic beams created from known spherical electric surface distribution may include full-wave simulations, geometric optics (GO), or physical optics (PO). These methods are well studied and accurate given the model fidelity and a suitable wavelength range. However, they cannot assess the incident and scattered electric field from multi-layered spherical objects without considerable computational effort. Fourier optics is a powerful method to obtain incident electric field, which can be easily expanded to vector spherical harmonics (VSH) presentation to accommodate spherical geometry. The VHS presentation is mapped with the T-Matrix method to evaluate the incident and scattered fields from the multi-layered dielectric sphere. The limitation of this method is that it is nominally compatible with planar interfaces. In this study, the Fourier optics method is expanded to model beam propagation from arbitrary electric field distributions positioned on spherical surfaces. The method is readily applicable to the field of THz sensing of corneal tissue hydration and geometry due to the cornea’s layered spherical shell geometry. This method can be expanded to synthesize an electromagnetic beam from electric field distribution positioned at any surface shape within a suitable wavelength.


    Wednesday 03.03, at 10:15, on Zoom MASTERS THESIS PRESENTATIONS

    Author:  Artem Lopatenko

    Title: Reduction mechanism of CO2 towards methane at Cu(100) with low water coverage investigated with density-functional theory

    Supervisor: Prof. Ilkka Tittonen

    Advisor:  Lassi Hällström

    Abstract: Copper is one of the most promising transition metals that electrocatalytically reduces a fraction of CO2 to hydrocarbons in an energy and resource e cient way. However, previous computational studies, mostly conducted with the density-functional theory (DFT), have a lack of consensus regarding the first intermediate, the rate-determining step and the preferred pathway in the CO2 reduction reaction (CO2RR) at Cu surface. In this study, two fundamental DFT functionals, namely the PBE and the PBEsol are examined in order to enhance understanding in reaction mechanism for CO2RR with single water molecule as part of the Langmuir-Hinshelwood mechanism occurring at Cu(100). Hence, an entire pathway from carbon dioxide to methane and corresponding potential dependent electrochemical analysis is investigated in the framework of this mechanism.

    ********************************************************************

     Author: Maribel Puentes Gruezo

    Title: Plasmonic nanoparticles: Using gold nanostructures as nano-sources of heat to enhance the photothermal effect of an evaporation device

     Supervisor: Ilkka Tittonen

    Thesis advisor: Ornella Laouadi

    Abstract: Plasmonic nanoparticles and their strong light-matter interactions have been the focus of numerous studies due to their promising applications. When subjected to illumination a metal nanoparticle features the mentioned phenomena, where the conduction electrons of the metal nanostructure resonate with the electromagnetic waves. This renders an enhanced light absorption; thus, a residual heat remains. Along these lines plasmonic nanostructures could potentially be used as optimal light-controlled sources of heat.

    In this thesis project gold nanoparticles are used as heat sources for efficient utilization of solar light. For this purpose, an evaporation device consisting of a porous, broadband absorbing, carbon black photothermal, film was functionalized by the addition of different gold nanoparticle structures fabricated using wet chemistry methods. The geometry and size where the parameters used for tuning the absorption cross-section of the particles. By integrating random sized, anisotropic shaped gold nanostructures, the resultant system is expected to have a faster temperature rise and a more efficient electricity generation than the non-functionalized carbon setup.

    *******************************************************************************
    Author: Shihan Zhao

    Title: Water splitting on thin film hematite electrodes with Ruthenium dioxide nanoparticles

    Supervisor: Prof. Ilkka Tittonen

    Advisor: Camilla Tossi

    Abstract: Photoelectrochemical (PEC) water splitting process can decompose water into hydrogen and oxygen with photocatalyst and solar energy. Hematite is a promising photocatalyst with its abundant reserves, low costs, chemical stability and an appropriate bandgap. In PEC water splitting process, hematite can achieve the water splitting process by moving the photogenerated charges to the electrolyte solution and Ruthenium dioxide is a potential co-catalyst which can accelerate this transporting process. The aim of the thesis is to improve the water splitting performance of hematite with the help of photo-deposition of Ruthenium dioxide nanoparticles and understand the effects of different photodeposition variables.

    In the experimental section, evaporated 10nm thick iron was baked to hematite in an oxygen atmosphere for different times to study the influence of Indium doping. The samples were then photodeposited with Ruthenium nanoparticles with different recipes of precursors solution and exposing time. RAMAN, EDX, AFM and SEM measurements are executed to analyze the sample element components and sample surface morphology. A basic PEC cell was constructed to execute linear sweep voltammetry and electrochemical impedance spectroscopy measurements.

    The obtained results show that with the photodeposited Ruthenium dioxide, the highest current density of the samples was three times larger than the bare hematite at 1.23V, which was a significant improvement. The onset potential was found to be shifted from 1.0V to 0.8V and there also appeared a small peak at around 0.5V due to the Ruthenium dioxide nanoparticles. The results also show that the concentration of methanol indeed influenced the shape and distribution of Ruthenium dioxide nanoparticles. One concern in the experiment is the instability of Ruthenium dioxide nanoparticles, thus in the future, potential steps, such as annealing and applying other co-catalyst on the top, can be applied to improve its electrochemistry stability. Furthermore, the assembly methods of the photoelectrode could be improved to reduce the number of failed samples.


    Wednesday 24.02, at 10:15, on Zoom
    Sofia Suutarinen, Aalto(Finland)
    Title: TBD (Master's Thesis Presentation)
    Abstract: TBD

    Wednesday 17.02, at 9:00, on Zoom

    Dr. Viktar Asadchy, Stanford University, USA: "Sub-Wavelength Passive Optical Isolators Using Weyl Semimetals"

    Abstract: In this talk, I will present the design of sub-wavelength passive non-reciprocal optical devices using recently discovered magnetic Weyl semimetals. These passive bulk topological materials exhibit anomalous Hall effect which results in giant magneto-optical effects and in principle can operate without external magnetization. The designed isolators have dimensions that are reduced by three orders of magnitude compared to conventional magneto-optical configurations. Our results indicate that the magnetic Weyl semimetals may open up new avenues in photonics for the design of various nonreciprocal components.


    Wednesday 03.02, at 10:15, on Zoom

    Prof. Marco Di Renzo, CNRS & Paris-Saclay University: "Reconfigurable Intelligent Surfaces for Wireless Communications"

    Abstract: Reconfigurable intelligent surfaces (RISs) have recently emerged as the new wireless communication research frontier with the goal of realizing metamaterial-coated smart and reconfigurable radio propagation environments via passive and tunable signal transformations. Featured by orders of magnitude lower hardware and energy cost than traditional active antenna-arrays and yet superior performance, RISs are the new driving technology for future wireless networks, especially for enabling them to migrate to higher frequency bands. RISs have the inherent potential of fundamentally transforming the current wireless network with active nodes solely into a new hybrid network comprising active and passive components co-working in an intelligent way, so as to achieve a sustainable capacity growth with a low and affordable cost and power consumption. Therefore, RISs have the potential to change how wireless networks are currently designed, usher in that hoped-for wireless future, and are regarded as an enabling technology for realizing the emerging concept of metamaterial-assisted smart radio environments (SREs). RIS-assisted SREs are a multidisciplinary research endeavor but are not well-understood. In this talk, I will introduce the state of the art, the research challenges, and some recent research results at the crossroad of wireless communications, electromagnetics, physics, and metamaterials. Source: arXiv:2004.09352 (IEEE JSAC, Nov. 2020).

    Wednesday 20.01, at 16:00, on Zoom

    Dr. Younes Ra’di, Advanced Science Research Center (ASRC), The City University of New York, USA: "New Frontiers for Advanced Wave Manipulation"

    Abstract: In this talk, first I will discuss highly efficient metasurfaces and metagratings that go beyond the fundamental physical limits of conventional artificial structures. Several examples of advanced structures with promising industrial potentials such as wireless power transfer, biomedical sensing, and teleportation of electromagnetic waves through nearly fully reflective walls based on parity-time-symmetric structures will be discussed. Next, I will talk about temporal shaping of electromagnetic waves that opens unprecedented possibilities in wave-matter interactions. I will discuss how using this concept we can go beyond several long-held fundamental limitations of conventional concepts such as critical coupling. Furthermore, I will discuss some of our interdisciplinary research efforts on translating the fascinating wave phenomena observed in circuit theory, electromagnetics, and optics to waves from different nature such as acoustic and elastic waves.

    -----------------------------------------------------------------

    ELE seminar Fall 2020

    Wednesday 16.12, at 10:15on Zoom

    Master thesis presentations:

    Matti Kuosmanen: "Improving radiation efficiency with characteristic mode analysis". Abstract: The characteristic modes analysis (CMA) has become a popular design and analysis method in the antenna community. It provides deeper insight into the physical operation of the antenna. To date, CMA has mainly been used for perfect electric conductors, whereas dielectric and lossy materials have attracted less attention. This presentation reviews the current research concerning the characteristic mode analysis of lossy structures. The focus is on lossy dielectric materials and how they affect the radiation efficiency of the antenna. The feasibility of modal analysis is evaluated in the case of mobile devices under the user's effect.

    Harri Varheenmaa, "Multiple-input multiple-output considerations for mobile phones in low band". Abstract: In this thesis, a 4x4 multiple-input multiple-output (MIMO) mobile antenna at the low band (824-960 MHz) is designed with narrow (2 mm) ground clearance. Design is based on the characteristic mode analysis (CMA). The antenna is manufactured and measured to verify the operation. 

    Chen Lingyi, "Analysis of brominated flame retardants in plastics by reflectance spectroscopy". Abstract: In the recycling process, waste plastics that contain brominated flame retardants (BFR) should be removed and recycled separately. This thesis concentrates on extracting the relation between BFR concentration in plastics and the infrared spectral information. Partial least squares (PLS) regression model is built to predict the BFR concentration in model plastics samples. The k-nearest neighbors (k-NN) classification model is used to separate waste plastics containing different levels of BFR concentration.

    https://aalto.zoom.us/j/62530104433


    Wednesday 9.12, at 10:15on Zoom
    Dr. Jingjing Chen, Huawei Technologies Sweden AB: Opportunities and challenges of 5G millimeter wave mobile terminals: an approach from the system analysis

    Abstract: Driven by 5G, millimeter wave has been introduced thanks to the wide spectrum, low latency, and higher data traffic. However, there are various challenges to overcome in order to implement millimeter-wave modules into modern mobile phones, such as limited space and sensitive EM environment. The Gothenburg terminal team will share the opportunities and challenges of millimeter wave in mobile terminal applications, in particular using the system analysis approach to provide design guidelines.

    Speaker Bio: Jingjing Chen holds a PhD degree in Microwave Electronics from Chalmers University of Technology, Sweden. During her PhD study and 7-year employment at Ericsson Research, she worked with mmW point-to-point communication links at E-band (70/80 GHz) and D-band (140 GHz) for mobile backhaul networks. She has been with Huawei Gothenburg Research Center over one year, leading a research team working with mmW mobile terminal technologies from system analysis, antenna design, to mmW RFIC design perspectives.

    https://aalto.zoom.us/j/64599122342


    Wednesday 11.11, at 10:15on Zoom

    Prof. Alex Jung (Aalto University, Computer Science): Basic Principles of Machine Learning, tutorial lecture

    Abstract: 

    From an engineering point of view, the field of ML revolves around developing software that implements the scientific principle: (i) formulate a hypothesis (choose a model) about some phenomenon, (ii) collect data to test the hypothesis (validate the model) and (iii) refine the hypothesis (iterate). A plethora of ML methods is obtained by combining different choices for the hypothesis space (model), the quality measure (loss) and the computational implementation of the model refinement (optimization method).

    Lecture slides are available here.

    --------------------

    Wednesday 4.11, at 16:00on Zoom

    Prof. Do-Hoon Kwon, University of Massachusetts Amherst, USA: Holistic lossless functional surface design via complete boundary field synthesis

    Abstract: 

    For power-preserving electromagnetic wave-transformation applications, synthesis of impedance boundaries that leads to a pointwise lossless surface characterization is presented for impenetrable surfaces. To a given set of propagating-spectrum input and output waves specified by the desired application, a set of evanescent surface waves bound to the surface are introduced and optimized such that the surface becomes locally and globally lossless. With exact Maxwellian fields specified as the total fields, the resulting lossless metasurface performs the envisioned wave transformation with a perfect power efficiency in principle. Applicable to both planar and curved surfaces, the new surface field synthesis technique enables novel functionalities as well as improves existing device designs. The principle behind the holistic impedance surface synthesis will be presented followed by impenetrable surface applications, where a design characterized by an inhomogeneous, scalar surface impedance represents a reciprocal and lossless surface. The surface parameters and full-wave simulation results will be shown for anomalous plane-wave reflectors, two-dimensional leaky-wave antennas, and a metasurface cloak for a circular cylinder in free space. At microwave frequencies, the designed metasurfaces may be realized using one or more layers of printed subwavelength resonators on dielectric substrates.

    Bio: Do-Hoon Kwon received the B.S. degree from Korea Advanced Institute of Science and Technology (KAIST), Korea in 1994, and the M.S. and Ph.D. degrees from the Ohio State University, Columbus, OH in 1995 and 2000, respectively, all in electrical engineering. He was a senior engineer with the Central R&D Center and Samsung Advanced Institute of Technology of Samsung Electronics in Korea from 2000 to 2006. During 2006–2008, he was a post-doctoral researcher with the Material Research Science and Engineering Center and the Department of Electrical Engineering of the Pennsylvania State University. In 2008, he joined the Department of Electrical and Computer Engineering, University of Massachusetts Amherst. During the 2016–2017 academic year, he was a visiting professor at the Department of Electronics and Nanoengineering, Aalto University, Finland. His main research interests include engineering electromagnetics for antennas and arrays, microwave metamaterials and metasurfaces, and cloaking. He is a senior member of the IEEE.

    https://aalto.zoom.us/j/64437319724

    ---------------------
    Friday 16.10 at 9, on Zoom

    Public examination of the doctoral dissertation “5G antennas for mobile phones and base stations” by Resti Montoya Moreno.

    Opponent: Prof. Wonbin Hong, Pohang University of Science and Technology, Republic of Korea

    --------------

    Tuesday 13.10, at 14:00on Zoom

    Dr. Mohammad Sajjad Mirmoosa: My research visit to EPFL: studies of time-varying particles and materials

    Abstract: 

    1 - In communities such as nanophotonics, plasmonics, metamaterials, and photonic crystals, people have mainly investigated the interaction of electromagnetic waves/light with inclusions, meta-atoms, natural/artificial materials which are static and time-invariant. However, one may suggest that those inclusions, meta-atoms, and materials can be properly engineered or modulated in time by using some external force, and, therefore, he/she brings another degree of freedom for manipulation of the wave in a desired way. Probably, in the context of classical electrodynamics, having this temporal modulation takes us to the most extreme scenario of wave-matter interaction. However, the problem is not straightforward. As expected, we know that the conventional definitions may not be applicable anymore, and we need to first revisit the fundamental principles. In this presentation, inspired by other branches of Electrical Engineering: Communications engineering and control engineering, I will simply talk about some of those fundamental principles which significantly help us in future to correctly understand the interaction of small time-varying inclusions/nanoparticles and linear time-varying natural/artificial materials with waves. 

    2- Also, following my research visit to Swiss Federal Institute of Technology in Lausanne, I will discuss some advantages of being a researcher at Aalto University, and, also, I will explain some of the points which we need to consider in order to increase the scientific level of the Department of Electronics and Nanoengineering (note that these are my personal views and can be surely criticised). 

    Join Zoom Meeting

    https://aalto.zoom.us/j/62501769187

    --------------------------

    Wednesday 7.10, at 10:15on Zoom

    Dr. Ana Díaz-Rubio: Engineered dual-physics reflectors

    ---------------------------------
    Thursday 17.09, at 11:15on Zoom
    Doru-Stefan Irimescu will present his Master’s Thesis on Thursday 17th, September at 11:15 in ZOOM.

     The topic of the thesis is: ‘A hardware and software platform for characterization and prototyping of a low-power energy-harvesting SoC ‘

    Thesis Supervisor: Kari Halonen

    -------------------------------

    Friday 11.09, at 10:00, on Zoom

    On behalf of the AP/MTT/ED Chapter of the IEEE Finland Section, we will host a very interesting talk on phased-array antennas for 5G and satcom.

     Dr. Martinez-Vazquez of IMST GmbH, Germany "RF challenges in the design of phased-array antennas for 5G and satcom communications systems"

    Friday 11 September 2020, 10:00-11:00.

    Some more details at https://events.vtools.ieee.org/m/238931


    -------------------------------
    Friday 11.09 at 12:00, on Zoom

    Mr. Mikko Heino doctoral thesis defense: antenna array technologies for 5G and beyond.

    Opponent: Dr. Marta Martínez-Vázquez, IMST GmbH, Germany

    Supervisor: Professor Katsuyuki Haneda, Aalto University School of Electrical Engineering, Department of Electronics and Nanoengineering

    Thesis available at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/

    Zoom Quick Guide: https://www.aalto.fi/en/services/zoom-quick-guide