Andre Vander Vorst

Andre Vander Vorst
Université Catholique de Louvain - UCLouvain | UCLouvain · Department of Electrical Engineering

About

162
Publications
25,360
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,489
Citations

Publications

Publications (162)
Article
Full-text available
Clinical research aiming at objectively identifying and characterizing diseases via clinical observations and biological and radiological findings is a critical initial research step when establishing objective diagnostic criteria and treatments. Failure to first define such diagnostic criteria may lead research on pathogenesis and etiology to seri...
Article
Full-text available
Recounts the career and contributions of Roberto Sorrentino.
Article
Full-text available
Presents information on recent EuMA and European Microwave conferences and events.
Article
Full-text available
The purpose of this paper is twofold. It first describes how Microwaves were progressively organized by Professional Engineering Institutions in Europe in the years 1960-2000, essentially through individual efforts over many years. The first formal Microwave event organized in Europe was the European Microwave Conference in London, 1969, opening a...
Article
Full-text available
Hyperthermia is a cancer treatment method used in combination with the classical therapies for enhancing the temperature of cancerous cells. In this paper we present a simple method to obtain an enhancement of the SAR (Specific Absorption Rate), which is one of the requirements to achieve a good thermotherapy treatment. By using the CST Microwave S...
Article
Full-text available
A flexible and dual-frequency microstrip applicator for microwave local hyperthermia is described. It is designed on conformal liquid crystal polymer (LCP) substrate and operating at ISM (Industrial, Scientific and Medical) frequencies of 915 MHz and 2.45 GHz. To conform the body’s curvature, the applicator is bent on a cylindrical body. 3D electro...
Article
Full-text available
A low cost, simple Broadband planar inverted F antenna (PIFA) is presented in this paper. The size of the proposed antenna is 40×10×12 mm3 and is suitable to be embedded in a mobile phone as an internal antenna. It can be achieved a broad bandwidth at VSWR
Article
Full-text available
This paper describes some key points in the history and development of the European Microwave Conference, the European Microwave Week, and the European Microwave Association, starting from 1969. It captures the way in which the conference since the earliest days has sought to create a successful blend of scientific and industry interests and has ad...
Article
Full-text available
This paper summarizes the results of experimental research on biological effects induced by electromagnetic exposure to low-level microwaves. We exposed four-month-old Wistar albino rats during 21 months to two different microwave frequencies and exposure modes, 2 h a day, seven days a week. In order to assess possible biological effects of microwa...
Article
This paper describes the design of embedded-grating n<sup>+</sup>-i-n<sup>+</sup> traveling-wave photodetectors (TWPDs). In the ideal case of perfect electrically matched photodetectors, the TWPD bandwidth is determined by the velocity mismatch between the group velocity of the optical beam and the phase velocity of the electrical photogenerated si...
Conference Paper
Full-text available
A low cost, simple broadband planar inverted F antenna (PIFA) is presented in this paper. The size of the proposed antenna is 40times 10 times 12 mm<sup>3</sup> and is suitable to be embedded in a mobile phone as an internal antenna. It can be achieved a broad bandwidth at VSWR <2 about 830 MHz (1780-2610 MHz) covering DCS, PCS, DECT, UMTS, Bluetoo...
Article
Full-text available
Introduction of the Session and of the speakers, and some reminders about the first three European Microwave Conferences: London 1969, Stockholm 1971, and Brussels 1973.
Conference Paper
Full-text available
The concept of a European Microwave Conference was developed before the first EuMC London 1969. Several actors have been instrumental. Some details on the first EuMC are described.
Article
Full-text available
The European Microwave Week (EuMW), held at the city of Amsterdam, the Netherlands, outlined the history of EuMW and highlighted the role of the European Microwave Association (EuMA). The conference emphasized that EuMC became an annual event and later was organized with the support of a professional conference manager (MEPL), in association with a...
Article
Written by distinguished experts in the field, RF/Microwave Interaction with Biological Tissues discusses the biological effects and applications of radio frequency and microwave fields. Chapters cover: Fundamentals in Electromagnetics; RF/Microwave Interaction Mechanisms in Biological Materials; Biological Effects; Thermal Therapy; EM-wave Absorbe...
Conference Paper
Full-text available
In the present study we examine the effect of microwave exposure to a GSM-like frequency of 970 MHz pulsed waves on the memory in rats by means of an object recognition task. Two populations of Wistar albino rats, each composed of 2 subgroups of 32 rats, have been exposed to low level radiofrequent radiation for 2 hours/day during 2 and 15 months,...
Conference Paper
Full-text available
The general public applications of microwaves are essentially the cellular phone and the microwave oven. Some years ago, articles in the national and international press started to express concern about cancer incidences among radar technicians and people housed in the neighborhood of antenna base stations. In this study, a possible link between mi...
Article
Full-text available
This paper reports on historical prospective on the establishment and purpose of the European Microwave Association (EuMA). The EuMC was first established in the fall of every odd year, beginning in London in 1969, then Stockholm in 1971, and Brussels in 1973. Starting with Montreux in 1974, the EuMC became an annual event and was organized with th...
Chapter
RF and Microwave Frequency RangesFieldsElectromagneticsRF and Microwave EnergyPenetration in Biological Tissues and Skin EffectRelaxation, Resonance, and DisplayDielectric MeasurementsExposureReferencesProblems
Chapter
Introduction to ThermotherapyHeating PrincipleHyperthermiaMethod of ThermometryReferencesProblems
Chapter
AbsorptionNervous SystemCells and MembranesMolecular LevelLow-Level Exposure and ELF ComponentsEar, Eye, and HeartInfluence of DrugsNonthermal, Microthermal, and Isothermal EffectsEpidemiology StudiesInterferencesRadiation Hazards and Exposure StandardsReferencesProblems
Chapter
IntroductionTransmission Lines and Waveguides for Medical ApplicationsAntennasRF and Microwave AblationPerfusion ChamberRF Gastroesophageal Reflux DiseaseEndometrial AblationMicrowave Measurement Techniques: ExamplesFuture ResearchReferencesProblems
Chapter
Foundation of EM Wave AbsorbersClassification of Wave AbsorbersFundamental PrincipleFundamental Theory of EM Wave AbsorbersApplication of EM AbsorberEM Wave Absorbers Based on Equivalent Transformation Method of Material ConstantMethod for Improving RF Field Distribution in a Small RoomReferencesProblems
Book
From engineering fundamentals to cutting-edge clinical applications This book examines the biological effects of RF/microwaves and their medical applications. Readers will discover new developments in therapeutic applications in such areas as cardiology, urology, surgery, ophthalmology, and oncology. The authors also present developing applications...
Article
Full-text available
The IEEE MTT-S is served by a number of technical committees (currently 23) that monitor and promote technical activities in specific areas within the domain of interest of the Society. The following report from Technical Committee MTT-10 on biological effects and medical applications is a survey of some of the research frontiers in the field of in...
Article
A fully analytical small-signal model for investigating the frequency response of submicrometer n<sup>+</sup>-i-n<sup>+</sup> traveling-wave photodetectors is derived. In order to properly account for nonstationary nonlocal phenomena characterizing submicrometer devices, the simple diffusive description of the carrier drift flux in a local driving...
Conference Paper
Full-text available
There is evidence that radio frequencies (RF) and microwaves directly affect living systems, as indicated by in vivo absorption experiments. Evidence is also provided by in vitro studies, revealing effects at various frequencies and intensities, on a number of cellular endpoints, including calcium binding, proliferation and alteration in membrane c...
Article
Full-text available
A theoretical model is proposed for the evaluation of dielectric properties of the cell nucleus between 0.3 and 3 GHz, as a function of its nucleic acids (NA) concentration (CNA). It is based on literature data on dielectric properties of DNA solutions and nucleoplasm. In skeletal muscle cells, the specific absorption rate (SAR) ratio between nucle...
Chapter
Full-text available
In the electromagnetic spectrum, microwaves are the waves whose wavelengths are comparable to ordinary laboratory dimensions. Furthermore, smooth surfaces of good conductors form very perfect reflectors for them. As a consequence, an electromagnetic wave in a reflecting pipe is reflected back and forth from wall to wall, so that it can travel to la...
Article
A fully analytical small-signal model is developed for the frequency response of traveling-wave photodetectors. It takes into account the dependence of the equivalent transmission-line admittance on the position, induced by the nonuniform distribution of the optical beam along the traveling direction. Moreover, the influence of the bias voltage on...
Article
Full-text available
An overview of microwave activities and infrastructures in Europe is presented. The material is organized in 17 sections, each devoted to a country or group of countries and prepared by an. internationally renowned microwave expert. In general, each section contains some history of microwaves in the region, and highlights some microwave activities...
Article
Full-text available
Medical applications of RF/microwaves are highlighted in this paper. The emphasis is placed on newer emerging diagnostic and therapeutic applications, such as microwave breast cancer detection, and treatment with localized high power used in ablation of the heart, and liver, benign prostate hypertrophy, angioplasty, and others. A very brief outline...
Article
Full-text available
This paper presents a novel fully analytical model describing the high-frequency behavior of p-i-n photodiodes. The transport equations are solved, taking into account the dependence of the carrier velocities on the electric field, while the RC-product effect is considered by adding the displacement current in the current equations. The model yield...
Article
Full-text available
Migration is a common name for processing techniques that try to reconstruct, from the dat recorded at the surface, the reflecting structures in the sub-surface. Most of the existing migration techniques do not take into account the characteristics of the acquisition system and the ground characteristics. We propose a novel migration method, applic...
Article
Using commercial and homemade simulation tools, this letter investigates how the geometrical and technological parameters of the p-i-n junction, particularly the p(+)- and n(+)-regions, influence the electrical and optical performances of GaAs p-i-n lumped and traveling-wave photodetectors (TWPDs). It is concluded that, for TWPDs, the electrical ba...
Article
Full-text available
A common way of describing antennas in the time domain is by means of their impulse response. When the time-domain antenna equations are expressed in terms of the normalised impulse response (normalised IR), they become very simple to use, because all frequency-dependent antenna characteristics are included in the normalised IR. This paper describe...
Article
Full-text available
This paper summarizes the results of an experimental research of thermal effects induced by electromagnetic exposure to wireless mobile communication equipment. A series of experiments has been performed in order to examine the time evolution of the temperature of some body-part surfaces exposed to electromagnetic radiation emitted by global system...
Article
Full-text available
The effect of ground plane and dielectric truncations on the radiation pattern of a slot antenna etched in a substrate covered conductor plane of finite extent is modelled, measured and validated. The modelling method is based on the evaluation of analytical Green's functions and the numerical computation of single integrals. The importance of taki...
Article
Full-text available
In this paper, the time domain modelling of an indoor impulse UWB GPR systems (1GHz-5GHz), built in the scope of the HUDEM project, is presented. For an impulse UWB system, a time-domain modelling is an obvious choice. We explain how the antennas can be characterised by their normalised impulse response. By considering the antenna as a convolution...
Article
This paper presents a full four-port characterization for traveling-wave optoelectronic devices, in particular, traveling-wave photodetectors (TWPDs), resulting in a scattering matrix formalism, which can be used for passive as well as active devices. A set of coupled distributed equivalent circuits is proposed for modeling the device, taking into...
Article
The paper presents a short-term project on microwave planar circuits proposed to undergraduate students at Universite Catholique de Louvain, Belgium, in the frame of a basic course on microwave engineering. It helps the students to familiarize with all circuit aspects at microwaves and millimeter waves: they design, analyze, realize, and measure a...
Article
Full-text available
In this paper, the design and the modelling of an indoor impulse UWB GPR systems (1GHz-5GHz), built in the scope of the HUDEM project, is presented. For an impulse UWB system, a time-domain modelling is an obvious choice. We explain how the antennas can be characterised by their normalised impulse response. By considering the antenna as a convoluti...
Article
Full-text available
A transmission line analysis of the bow-tie antenna and the linearly tapered slot antenna (LTSA) is presented. These structures belong to the class of conical transmission lines defined here in terms of conical coordinates. A complete set of solutions of the Helmholtz equation is obtained exhibiting TE and TM modes. Modal fields are expressed by La...
Article
Full-text available
The copolar and cross-polar radiation patterns of the Vivaldi antenna on a dielectric substrate are calculated and validated by measurements. The method involves a two-step procedure. The electric field distribution across the antenna slot aperture is calculated first. The radiated fields are then calculated, using Green's functions. The continuous...
Conference Paper
Full-text available
Guidelines for limiting EM exposure provide protection against known adverse health effects. Biological effects, on the other hand, may or may not result in an adverse health effect. Main biological effects are reviewed: nervous system, cellular level, and molecular level. Some attention is given to devices affecting eye, ear, and heart. PW and ELF...
Conference Paper
Full-text available
This paper presents preliminary results of experiments concerning thermal effects due to electromagnetic exposure from handheld mobile communications equipment. A human head has been exposed to electromagnetic radiation emitted by different commercial mobile phones (900 MHz), and the consequent surface temperature variation has been measured by the...
Article
Full-text available
A full-wave analysis based on the moment method in the spectral domain is used to perform an analysis of the rectangular (quasisquare) patch antenna. The conventional rectangular patch shape excited by a coaxial cable at a point favoring the resonance of only one patch edge results in a very narrow bandwidth structure that radiates linear polarized...
Article
Full-text available
The full-wave analysis based on the moment method in the spectral domain is used to perform an analysis of the rectangular patch antenna working around 24 GHz. The resonant frequency is in good agreement with the measured result. The value of the relative permittivity which is taken is at 10 GHz, and the severe tolerances in the substrate thickness...
Article
Full-text available
This paper demonstrates that fully-depleted (FD) silicon-on-insulator (SOI) technology offers unique opportunities in the field of low-voltage, low-power CMOS circuits. Beside the well-known reduction of parasitic capacitances due to dielectric isolation, FD SOI MOSFETs indeed exhibit near-ideal body factor, subthreshold slope and current drive. Th...
Conference Paper
This paper investigates for the first time the microwave properties of arrays of magnetic nanowires embedded into a planar substrate. Our experiments show that the structure acts like an equivalent microwave ferrite substrate having several advantages. Resonances are indeed obtained in the measured transmission term of a microstrip transmission lin...
Article
The authors present a novel microstrip structure using a nanoscale porous substrate filled by a ferromagnetic material, forming an array of nanowires perpendicular to the ground plane. When compared with photonic bandgap structures, the stopband behavior is created here by a gyromagnetic resonance phenomenon in the metallic nanowires. This resonanc...
Article
We report on the microwave properties of arrays of parallel magnetic nanowires constituted of nickel, cobalt, or Ni/Fe alloy embedded in nanoporous track-etched polymer membranes. The experiments consist of transmission measurements carried out on microwave stripline structures using a magnetically loaded membrane as the substrate. Measurements wer...
Article
Full-text available
The paper presents an efficient design method for frequency-tunable planar devices using gyrotropic ferrite YIG films. The behaviour of the tunable YIG film is modelled by an equivalent lossy transmission line. Its parameters are the function of the permeability tensor components, which depend on the frequency and magnitude of the DC biasing magnet...
Article
Full-text available
This paper investigates the possible variational behavior of transmission-line parameters established for planar structures by using a nonquasi-transverse-electromagnetic full-wave formalism. A variational principle for the propagation constant is linked to the power flow and magnetic and electric densities of energy by means of a functional expres...
Article
In order to evaluate the performances of microwave technologies in land-mine detection, the electrical properties of soils have been extensively evaluated from 2 to 18 GHz both theoretically and experimentally, using a new transmission method, as a function of soil type and water content. This results in a new model for the microwave permittivity o...
Article
Full-text available
Published analyses of radiation modeling for slot structures on dielectric substrate are empirical or numerical. This paper proposes exact analytical asymptotic expressions of the far-field Green's functions of a surface magnetic current element on a perfect electric conductor plane covered by a lossy dielectric substrate of finite thickness. From...
Article
This paper presents a wide-band model describing the behavior of an open-ended microstrip line illuminated at its termination. The photoinduced carriers create a plasma at the end of the line, which modifies the complex dielectric constant and, therefore, also the field configuration. The perturbation due to the illumination is modeled by an optica...
Conference Paper
Full-text available
In the frame of the Belgian interuniversity project HUDEM (HUmanitarian DEMining), the Royal Military Academy (RMA) has started a research on the detection of plastic AP mines by means of ultrawideband ground penetrating radar (UWB GPR) i.e. GPR using ultra-short electromagnetic pulses (<200ps). Because AP mines are not buried at great depth and ar...
Conference Paper
This paper describes a new model for an open-ended microstrip line under illumination for the design of optically-controlled microwave devices. The model gives an analytical expression of the load impedance of the open circuit as a function of the line geometry and the electrical parameters of the substrate on which it is manufactured. Measurements...
Conference Paper
A new procedure for measuring the complex permittivity of liquids has been set up. It is based on measuring the scattering parameters of waveguide two-ports, up to 110 GHz, and on an original calibration method previously developed by the authors. Measurements describe the complex permittivity of biological and organic liquids at frequencies above...
Article
Full-text available
In this paper the layered structure of p-i-n photodetectors is modeled for the first time as a transmission line. The method of lines, as a two-dimensional (2-D) full-wave approach, is used to calculate the propagation constant. The numerical results agree well with measurements made on experimental devices over a frequency range of 1-30 GHz. An im...
Article
Full-text available
An original and general method is proposed to predict the impact of electromagnetic effects due to the environment on the error performance of microwave communications systems. The method is based on the concept of a process-oriented model which consists of a simplified representation of the physical phenomenon responsible for transmission impairme...
Article
Full-text available
In this article we present the analysis and simulation of nonlinearities in the GaInAs/InP p-i-n photodetector at high illuminations. It is shown that the nonlinearities are generated principally in the low-field region of the intrinsic layer. The frequency response, especially for the nonlinear characteristics, is illustrated to differ significant...
Article
Full-text available
In this article we present the analysis and simulation of nonlineariltes in the GaInAs/InP p-i-n photodetector at high illuminations. It is shown that the nonlinearities are generated principally in the low-field region of the intrinsic layer. The frequency response, especially for the nonlinear characteristics, is illustrated to differ significant...
Article
Full-text available
After a short review of the nervous system and its constituents, recent data on microwave bioeffects are reviewed and evaluated, in particular, the effects on the brain and the spinal cord and under low-level irradiation. Special attention is paid to new results on the effects of modulated and pulsed waves with respect to both continuous wave (CW)...
Article
Full-text available
Presents an in vivo experiment concerning cerebral evoked potentials in the presence and in the absence of microwaves irradiating the spinal cord. An electrical stimulus is applied on the peripheral nervous system of a rabbit while the impulse response (evoked potential) is measured by an electrode in the cortex. The spinal cord is irradiated at 4....
Conference Paper
This paper investigates for the first time the transmission line behaviour of a PIN photodiode at microwaves frequencies. Original theoretical models are developed for the complex propagation constant of this structure and compared with measurements carried out at U.C.L. It is shown that the classical methods found in the literature for characteris...
Article
Full-text available
We present in this article a high-speed silicon photoconductive switch by which electric pulses of amplitude higher than 1000 V and pulse widths of less than 30 ns have been obtained at a 50-O load under 1500-V dc biasing. During the preparation of the switches two novel techniques were introduced. These reduce the carriers' lifetimes considerably...
Conference Paper
Full-text available
A system of contactless stimulation of the sciatic nerve has been developed for caged mice.
Conference Paper
This paper presents microwave education facilities set up at U.C.L. for the five past years. Emphasis is led on the design, realisation and measurement of planar subsystems which components are progressively studied during the undergraduate education in electrical engineering at U.C.L. This is illustrated by the presentation of various realisations...
Article
Full-text available
Shielded multilayered structures are commonly used in MIC circuits up to 140 GHz. This paper describes an original method to accurately calculate the complex propagation constant of shielded multilayered structures with minimal computational effort. The method combines singular value decomposition and poles location technique. In order to construct...
Article
Full-text available
This article proposes a new approximate formula for determining the effectiveness of site shielding by a knife-edge obstacle, by adding a correction term to the ITU-R formula. The new formula is accurate to within 0.1 dB for diffraction angles less than 12° if the distance from obstacle to antenna is larger than 100 wavelengths, and to better than,...
Article
An unexpected nonreciprocal behavior is observed on Magnetostatic Forward Volume Waves (MSFVW) Straight Edge Resonators (SER's) using YIG films. The nonreciprocal effect is theoretically predicted by taking into account the demagnetizing effect of the DC biasing magnetic field when calculating the forward and reverse propagation constants of MSFVW...
Conference Paper
Full-text available
Presents an in-vivo experiment concerning cerebral evoked potentials of rabbits, without and with microwave irradiation of the spinal cord at 4.2 GHz. There is ample evidence of microwave effects. A first careful calculation of the absorbed power seems to show no evidence of a non-thermal effect on the nervous system