3556 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 59, NO. 10, OCTOBER 2011

Design of an Implantable Slot Dipole ConformalFlexible Antenna for Biomedical Applications

Maria Lucia Scarpello, Divya Kurup, Hendrik Rogier, Senior Member, IEEE, Dries Vande Ginste, Member, IEEE,Fabrice Axisa, Jan Vanfleteren, Member, IEEE, Wout Joseph, Member, IEEE, Luc Martens, Member, IEEE, and

Gunter Vermeeren

Abstract—We present a flexible folded slot dipole implantableantenna operating in the Industrial, Scientific, and Medical (ISM)band (2.4–2.4835 GHz) for biomedical applications. To make thedesigned antenna suitable for implantation, it is embedded in bio-compatible Polydimethylsiloxane (PDMS). The antenna was testedby immersing it in a phantom liquid, imitating the electrical prop-erties of the human muscle tissue. A study of the sensitivity of theantenna performance as a function of the dielectric parameters ofthe environment in which it is immersed was performed. Simula-tions and measurements in planar and bent state demonstrate thatthe antenna covers the complete ISM band. In addition, SpecificAbsorption Rate (SAR) measurements indicate that the antennameets the required safety regulations.

Index Terms—Bent antenna, implantable antennas, industrial,muscle tissue sensitivity, scientific andmedical (ISM) band, specificabsorption rate (SAR).

I. INTRODUCTION

I MPLANTABLE devices are becoming widely researchedfor different fields of applications, both for humans and

animals. Some examples of applications are: monitoring bloodpressure and temperature, tracking dependent people or lostpets, wirelessly transferring diagnostic information from anelectronic device implanted in the human body for human careand safety, such as a pacemaker, to an external RF receiver [1].Small implantable biomedical devices placed inside the humanbody may improve the lives of numerous patients. Patientswith the antenna implanted in the body regularly return tothe hospital for checkups, where their status and the statusof the implant are verified. With the use of RF technology,data recorded by the implanted antenna can be transmittedwirelessly to the receiving station, while the patient is waitingin the lounge. Some patients may require checks every day. Insuch case a home care unit can be placed in the patient’s home.The unit can communicate with the medical implant and can

Manuscript received June 10, 2010; revised November 23, 2010; acceptedApril 04, 2011. Date of publication August 04, 2011; date of current versionOctober 05, 2011.M. Scarpello, H. Rogier, and D. Vande Ginste are with the Electromagnetics

Group, Department of Information Technology (INTEC), B-9000 Gent, Bel-gium (e-mail: marialucia.scarpello@ugent.be).D. Kurup, W. Joseph, L. Martens and G. Vermeeren are with the Department

of Information Technology (INTEC), UGent-WiCa, B-9050 Gent, Belgium.F. Axisa and J. Vanfleteren are with the ELINTEC-TFCG, Technologiepark

914 B-9052 Gent, Belgium.Color versions of one or more of the figures in this paper are available online

at http://ieeexplore.ieee.org.Digital Object Identifier 10.1109/TAP.2011.2163761

be connected to the telephone system, or the internet, and senddata regularly to the responsible person at the hospital [2].The state-of-the-art of research in implantable antennas

shows that microstrip or planar-inverted F antennas (PIFA),operating in the 402–405 MHz Medical Implant Communi-cations Service (MICS) band, were simulated [3] and alsofabricated and measured [4]–[6]. The main issue with this kindof antennas, operating at 403 MHz and thus corresponding to awavelength of 744.4 mm in free space, is that it is not practicalto put them into a living human body without performing thor-ough miniaturization. Indeed, taking the effect of the body intoaccount during the design, reducing the antenna size by aroundseven times, without miniaturization it still remains too big tobe implanted. In [5], the designed antenna has a cylinder heightof 22.72 mm and an external radius of 10.5 mm, and so it isa small size antenna. However, the reflection coefficient valueshown in the paper is only simulated and not measured and thesimulated MICS bandwidth is only partially covered. In [6],the designed PIFA antenna is also small, i.e., 22.5 mm 18.5mm 1.9 mm, but its fractional bandwidth is 20% lower thanthe one of the antenna we propose and it is not embedded inany insulating biocompatible material during measurements.Choosing a higher resonance frequency, corresponding to

the Industrial, Scientific, and Medical (ISM) band (2.4–2.4835GHz), is one way to reduce the antenna size and making itavailable to be implanted. Another advantage has to do withthe radio communication link: the larger bandwidth allowsfor higher bitrates. Implantable H-shaped slot cavity antennasare studied for 2.45 GHz applications in [7], [8]. In [7], theantenna was simulated, whereas in [8] the same antenna wasreduced in size. But since the size was too small to be fabricated(2.8 mm 4.0 mm 1.6 mm), the antenna was rescaled tolarger dimensions to be manufactured and measured in orderto be able to compare measurements with the finite-differencetime-domain (FDTD) simulations. Radiation patterns, gain pat-tern, and radiation efficiency value are related to the rescaledantenna and to a rescaled resonance frequency equal to 980MHz. Moreover in [8], no biocompatible material was used toembed the antenna and the cable during the measurements. In[9], [10], two dual band implantable antennas are presented,working properly in the MICS band and in the ISM band.Measurements were performed in a human skin mimickinggel tissue and in a rat skin mimicking gel tissue, respectively.In [10], the gain pattern is simulated and its maximum valueis dBi in the ISM band. However, the two antennas arenot embedded in any biocompatible material and they are notflexible. In [11] a cardiovascular stent, working at 2.4 GHz

0018-926X/$26.00 © 2011 IEEE

SCARPELLO et al.: DESIGN OF AN IMPLANTABLE SLOT DIPOLE CONFORMAL FLEXIBLE ANTENNA FOR BIOMEDICAL APPLICATIONS 3557

has been designed, fabricated, and implanted in a live porcinesubject. The stents are left without any insulation material andthey are in direct contact with the tissue. In [12] three differentinhomogeneous digital phantoms are considered to check thedifferent radiation performances of wireless implants. Hereagain only simulations are performed but no measurements.In this paper, we present the design, characterization, and

measurements of an implantable antenna operating in the 2.45GHz ISM band, recommended by the European Radiocommu-nications Committee (ERC) for ultra-low-power active medicalimplants [13]. The antenna is a flexible slot dipole. To make theantenna suitable for implantation, it is embedded in biocompat-ible Polydimethylsiloxane (PDMS). The reflection coefficientwas simulated and measured in the MSL2450 liquid, providedby Speag (Zurich, Switzerland) [14], mimicking a 100% humanmuscle tissue, having well-defined dielectric values at 2.45GHz. To investigate how different human tissues, surroundingthe implanted slot dipole, affect its radiation characteristics,a study on the sensitivity of the liquid mimicking the humanmuscle tissue was performed. Thereto its dielectric nominalvalues were varied from 50% larger to 50% smaller. Thesesimulations were performed to ensure that the antenna isfunctioning properly in any type of body environment. Theradiation characteristics of the antenna in terms of E-field andgain were simulated by means of FDTD calculations. For theevaluation of performances and safety issues related to im-planted antennas, the 10-g and 1-g averaged specific absorptionrate (SAR) are measured and compared with the ICNIRP [15]and with the FCC guidelines [16].First, in Section II, the antenna design and its fabrication

are presented. Next, in Section III, the performance in termsof reflection coefficient is reported. Good agreement is demon-strated between the simulated and measured reflection coeffi-cient. In Section IV, the sensitivity of the antenna as a functionof the dielectric properties of the muscle tissue is analyzed, ver-ifying that the antenna can be placed close to different kindsof tissue. In Section V, the radiation characteristics of the an-tenna, including the measured SAR distribution, are shown. InSection VI conclusions are summarized.

II. BIOCOMPATIBLE FOLDED SLOT DIPOLE ANTENNA DESIGNAND MANUFACTURING PROCESS

The antenna, presented in this paper, is a flexible folded slotdipole embedded in biocompatible PDMS, as folded slot dipolegeometries can provide significantly larger bandwidths thanpatch antennas [17]. The top and frontal view of the antennaare shown in Figs. 1 and 2, respectively. The dimensions of thefolded slot dipole antenna are shown in Table I. The antenna isdesigned by means of the 2.5-D EM field simulator Momentumof Agilent’s Advanced Design System (ADS). The antennadesign procedure consists of three steps. First, the foldedslot dipole antenna was designed, using ADS’s optimizationroutines, to operate in the 2.45 GHz ISM band in free space.Second, one superstrate and one substrate of PDMS were addedto the design and, after the characterization of the PDMS, weredesigned and reoptimized the antenna embedded in siliconeso that it covers the ISM band. Third, in a last optimizationstep, on top of the superstrate and below the substrate one layer

Fig. 1. Top view of the coplanar waveguide-fed antenna.

Fig. 2. Frontal view of the coplanar waveguide-fed antenna.

of liquid, mimicking the dielectric characteristics of humanmuscle tissue at 2.45 GHz, was added. Finally, the antenna sodesigned have good simulations results, working properly inthe ISM band. To check more accurately, the antenna was alsosimulated with the 3-D simulator CST Microwave Studio andthe simulation results were still satisfactory. To manufacturethe antenna we rely on a flexible electronic technology. Aphotoresist film was spin-coated on a copper foil and patternedby UV radiation through a photomask; the patterned shape isshown in Fig. 1; two PDMS layers are used as substrate andsuperstrate, each with a thickness of 2.5 mm, to mould theantenna [18], [19]. The dielectric properties of the PDMS werecharacterized at 2.45 GHz, to be and .The feeding structure of the slot dipole antenna consists of

a coplanar waveguide (CPW) with a 50 mode impedance.Matching the mode impedance of the CPW to 50 is obtainedby tuning the distance between the tracks and , as well as the

3558 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 59, NO. 10, OCTOBER 2011

TABLE ISIZE OF THE FOLDED SLOT DIPOLE ANTENNA

Fig. 3. Top view of flex antenna without PDMS.

Fig. 4. Side view of antenna and cable embedded in PDMS.

width of the tracks (Fig. 1). The CPW is fed by a U.FL connectorand an ultra-fine Teflon coaxial cable supplied by Hirose [20].The U.FL connector is chosen (specifically for measurementspurposes) because it is compact and it suits the small CPW size.Both the connector and the cable are also embedded in PDMS.Fig. 3 shows the antenna prototype before being embedded inthe PDMS. Fig. 4 shows a side view of the antenna prototypewith its connector and cable after being embedded in the PDMS.

III. SIMULATION AND MEASUREMENTS

In real-life applications, the antenna is intended to be im-planted into the human body, subcutaneously, particularly insidethe muscle. Hence, the measurement setup, using a phantom, isas follows. The antenna is placed at the center of a plastic con-tainer of dimensions 80 cm 50 cm 20 cm filled with 30 litersof the Human Muscle Tissue liquid MSL2450 [14]. This liquid

TABLE IIDIELECTRIC VALUES OF MSL2450, AT DIFFERENT FREQUENCIES

TABLE IIIDIELECTRIC VALUES OF HUMAN MUSCLE TISSUE, AT DIFFERENT

FREQUENCIES, AS REPORTED IN [21]–[23]

Fig. 5. S11 values using the MSL2450 dielectric properties [14] (dotted line)and the human muscle tissue dielectric properties [21] (dashed line), comparedto the return loss value of the antenna immersed in a medium with fixed valuesof permittivity and conductivity, i.e., those of MSL2450 at 2.45 GHz (full line).

mimics the dielectric characteristics of human muscle tissue at2.45 GHz, standardized in [21] to be S/m,

kg/m . Dielectric values of the liquid at 2.45 GHzmeasured by the manufacturer result to be:S/m, kg/m [14]. In Tables II and III permittivity andconductivity values of the liquid MSL2450 at different frequen-cies, measured by the manufacturer, and of the human muscletissue [21]–[23] are listed, respectively.The values in Tables II and III cover the band (2.0 GHz and

3.0 GHz) in which the measurements were performed, and assuch also encompass the ISM band (2.4–2.485 GHz). Fig. 5 re-ports the values for each couple of dielectric values reportedin Tables II and III, valid at the specified frequency. It can be ob-served that the small differences in , reported in Tables IIand III, do not lead to very different antenna behavior. A thirdsimulation, where a fixed relative permittivity anda fixed conductivity S/m were used within the com-plete band, also indicates that the antenna is rather insensitiveto changes of the surrounding medium. This will be further il-lustrated by considering other human tissues (Figs. 9 and 10).Moreover, a detailed study of the sensitivity of the antenna as afunction of the dielectric properties of the liquid is reported inSection IV.

SCARPELLO et al.: DESIGN OF AN IMPLANTABLE SLOT DIPOLE CONFORMAL FLEXIBLE ANTENNA FOR BIOMEDICAL APPLICATIONS 3559

Fig. 6. Schematic representation of the reflection measurement setup for thedesigned implantable antennas using muscle tissue simulating liquid.

Fig. 7. SAR and reflection measurement setup with the implantable antennainside the liquid during a measurement.

The antenna is connected to a Rhode and Schwarz ZVR Net-work Analyzer, as shown in Figs. 6 and 7. Inside the phantom,

measurements are performed when the antenna is both inplanar and bent state.First, Fig. 8 displays a comparison between the measured and

simulated reflection coefficient of the antenna in planar state.The simulations are performed using the EM field simulatorMomentum of Agilent’s Advanced Design System (ADS) andCST Microwave Studio simulator. Since ADS Momentum is a2.5-D simulator, it does not account for the finite size of thePDMS layers. This finite size typically results in a shift of theresonance frequency to lower frequencies, so for the initial de-sign in Momentum, to cover the ISM band, the antenna is de-signed to resonate at 2.5 GHz. Once fabricated and measured,this design ensures that our antenna will cover the complete

Fig. 8. Antenna in planar state: reflection coefficient, simulations versusmeasurement.

Fig. 9. Three layers geometry for the design of the slot dipole antenna, placedin between fat and muscle.

Fig. 10. Five layers geometry for the design of the slot dipole antenna, placedin between two layers of muscle.

requested bandwidth, as also verified by CST simulations inFig. 8. The required dB impedance bandwidth of the an-tenna is 83.5 MHz in the 2.45 GHz ISM band. Simulations andmeasurements satisfy the requirements: (i) the antenna was sim-ulated in planar state with ADS. Its bandwidth is very wide,1.23 GHz (2.22–3.45 GHz), it includes different resonances ofthe antenna and the fractional bandwidth at the target frequency(2.45 GHz) is approximately 50.2%. (ii) The antenna was alsosimulated in planar state with CST: its bandwidth is 270 MHz(2.30–2.57 GHz) and the fractional bandwidth at the target fre-quency (2.45 GHz) is approximately 11.0%. (iii) Antenna mea-surements are performed to validate the simulations: the mea-

3560 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 59, NO. 10, OCTOBER 2011

TABLE IVDIELECTRIC VALUES OF FOUR DIFFERENT HUMAN TISSUES,

AT 2.45 GHZ, AS REPORTED IN [21]–[23]

Fig. 11. Simulation of the return loss of the antenna placed in the structures ofFigs. 9 (dashed line) and 10 (dotted line), compared to the antenna placed in theMSL2450 (full line).

sured bandwidth in planar state is 350 MHz (2.20–2.55 GHz)and the fractional bandwidth at the target frequency (2.45 GHz)is approximately 14.2%.Second, to demonstrate that the antenna can work within dif-

ferent human tissues, the antenna is placed into two human bodystructures, as reported in [24], [25] and shown in Figs. 9 and10, and simulated by means of ADS Momentum. The dielec-tric properties ( ), for each layer of the two structures, at

GHz, were obtained from [21], [22] and [23], andshown in Table IV.In Fig. 11, the return loss value of the antenna placed in the

structures of Figs. 9 and 10 is shown. A slight shift of the res-onance frequency towards higher frequencies can be observed,but the return loss value still remains below dB in the wholeISM band.Third, the performance of the antenna when it is bent, as such

making it conformal to curved parts of the body, is verified.Thereto, the antenna is bent around its x-axis using two cylin-ders with different diameters, 8 cm and 4 cm, and with a holein the middle, as shown in Fig. 12. The measured reflection co-efficient of the bent antenna is compared to the planar antennaand shown in Fig. 13. The reflection coefficients of the bent an-tenna exhibits a resonance frequency at 2.22 GHz. So it isobserved that the resonance has shifted to a somewhat lowerfrequency, compared to GHz for the planar antenna.Still, the bandwidth of 350 MHz is maintained and the completeISM bandwidth is covered.

IV. SENSITIVITY OF THE ANTENNA TO DIELECTRICPROPERTIES OF THE MUSCLE TISSUE

The use of a muscle tissue liquid is widely accepted as a stan-dard, as it is very important to experimentally verify the charac-

Fig. 12. Cylinders used to bend the antenna: 8 cm and 4 cm diameter.

Fig. 13. Antenna bent around x-axis versus antenna in planar state: reflectioncoefficient measurements.

teristics of electromagnetic (EM) propagation inside the humanbody. Muscle tissue exhibits typical anisotropic electric prop-erties [26]: in the low frequency range, the longitudinal con-ductivity is significantly higher than the transverse conductivity[27]. A variation of conductivity can influence the performanceof antennas in real life applications. Fortunately, the muscletissue anisotropy is frequency dependent: if the frequency of thecurrent is high enough (i.e., in the MHz range), the anisotropicproperties disappear [28]. In this paper, the operation frequencyof the antenna is from 2.4 GHz to 2.485 GHz, high enough toneglect the effect of anisotropy. Moreover, the effect of toler-ances in the dielectric properties of the different tissues can besignificant, potentially influencing communication performanceof the implantable slot dipole antenna. Using ADS Momentum,a parametric study is performed that determines the influence ofthe muscle tissue’s permittivity and conductivity on the reflec-tion coefficient of the antenna, in terms of resonance frequencyand fractional bandwidth. This is to ensure that the antenna canbe implanted at different locations inside the body, also close totissues having different dielectric characteristics. The electricalproperties of themuscle tissue liquid at 2.45 GHzwere standard-ized in [21] to be S/m, kg/m .

SCARPELLO et al.: DESIGN OF AN IMPLANTABLE SLOT DIPOLE CONFORMAL FLEXIBLE ANTENNA FOR BIOMEDICAL APPLICATIONS 3561

TABLE VRESONANCE FREQUENCY [GHZ] AND REFLECTION COEFFICIENT [DB] FOR SOME COUPLES OF AND VALUES

For the MSL2450 liquid, slightly different values were mea-sured by the manufacturer, resulting inS/m, kg/m at 2.45 GHz [14]. The dielectric charac-teristics are now varied as follows:

(1)

where and are the nominal values of the liquid, corre-sponding to the values measured by the manufacturer.Varying and , according to (1), results in

simulations. 25 relevant samples are shown in Table V. At thedielectric nominal values, the fractional bandwidth equals 50%,the antenna resonates at 2.51 GHz and dB. Forall the other simulations the fractional bandwidth is always be-tween 48.5% and 51.5%. In the worst case dB,for . For all considered variations in dielectric prop-erties, the complete ISM band remains covered and thedB bandwidth results to be very large, showing the lowest fre-quency equals to 2.2 GHz and the highest one equals to 3.5GHz. As stated before (Section III), the antenna was designedin ADS-Momentum to resonate at 2.5 GHz to account for a pos-sible shift to lower frequencies due to the finite size of the an-tenna. As can be seen from the Table V, the largest shift can beexpected when the relative permittivity of the muscle tissue isdrastically lower than its nominal value and when the losses aremuch higher . Still, the shift of the resonancefrequency is limited. Therefore, we conclude that the antennaworks properly in various human bodies, with considerably dif-ferent dielectric properties.

V. RADIATION CHARACTERISTICS OF THE ANTENNA

Using CST Microwave Studio simulations, the radiationcharacteristics of the antenna inside the liquid simulatingmuscle tissue are determined in terms of radiation patterns andgain. To simulate, for example, the implanted antenna in thehuman arm, the dimensions of the box containing the liquid arechosen to be 180 mm 60 mm 60 mm, as shown in Fig. 14.The antenna is directed toward the surface of the skin (surfaceof the box), and along the z-direction the distance to the surfaceof the skin is set to 4 mm. In the x-y plane, the antenna is placedin the center of the surface of the human model arm (centerof the box). This setup is the same as in [8]. The computedradiation patterns in the -plane and the -plane

Fig. 14. CST numerical calculation model: the box simulates a human arm.

Fig. 15. Far-field pattern at 2.45 GHz in the -plane, y-z plane.

are shown in Figs. 15 and 16. The patterns arecomputed at 2.45 GHz, at a reference distance of 1 m, andusing an input power of 1 W. Fig. 17 shows the antenna gain.The maximum gain is equal to dBi for and

and the radiation efficiency is 0.14%. These valuesare comparable to other results in literature, such as in [8]. Theradiation efficiency value is very low because the antenna isnot in free space, but embedded inside a human arm, simulatedas a very lossy medium.The SAR is measured in a 3 cm 3 cm 2.5 cm cube above

the antenna, as reported in Fig. 18. The measurement setupis provided by Speag (Zurich, Switzerland). The measurementsystem used is DASY 3 [29] and the phantom is filled with theliquidMSL2450 [14]. The size of the box phantom [30] has been

3562 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 59, NO. 10, OCTOBER 2011

Fig. 16. Far-field pattern at 2.45 GHz in the -plane, x-y plane.

Fig. 17. Gain pattern at 2.45 GHz.

Fig. 18. Setup for SAR measurements.

chosen to correspond to the average trunk of an adult man. Be-cause sharp edges can cause field modifications, the edges arerounded with a radius of 7 cm. The SAR measurement probe isEX3DV4 [31]. The SAR measurement procedure is describedin [32]. Fig. 19 shows the SAR distribution on the x-y planeof the antenna at when the input power is 2 mW: thepeak SAR value is 0.308 W/Kg. The 10-g averaged SAR peakvalue is 0.032 W/Kg and the 1-g averaged SAR peak value is

Fig. 19. SAR distribution for an input power of 2 mW.

0.079W/Kg. These values fulfill the ICNIRP [15] and FCC [16]guidelines for general public exposure.

VI. CONCLUSION

The design, manufacturing, measurement, and sensitivitystudy of a flexible folded slot dipole antenna embedded inPDMS for implantation into the human body was performed.The human body was replaced by a human muscle tissueliquid with known dielectric nominal values. The main issuesaddressed in this paper are:1) design of a slot dipole antenna suited for implantation intothe human body;

2) evaluation of the characteristics of the antenna in terms ofreflection coefficient in planar and bent state, E-field andgain;

3) study of the sensitivity of the liquid mimicking the humanmuscle tissue, varying its nominal dielectric values;

4) checking the SAR limitations, by means of SAR measure-ments.

Measurements and simulations of the reflection coefficient inplanar and bent state in the 2.45 GHz ISM band demonstratea very large bandwidth in both states, fully covering the ISMband. A good agreement is found between simulations and mea-surements for the planar state antenna. In bent state, a shift ofthe resonance towards lower frequencies is verified during mea-surements. The simulated far-field pattern and gain at 2.45 GHzshow a dBi gain at and . The studyof the sensitivity with respect to the dielectric properties of sur-rounding tissue shows that the EM characteristics of the antennaare stable for a wide range of tissue properties in the neighbor-hood of the antenna. In fact, only for extreme changes of the di-electric properties, the resonance frequency starts shifting. Themeasured SAR values with an input power of 2 mW averaged in1-g and 10-g tissue show that the antenna respects the ICNIRPand FCC guidelines for general public exposure. In the future,integration of the required transceiver and power supply is en-visaged to realize an implantable system for biotelemetry ap-plications, completely embedded in biocompatible silicone and

SCARPELLO et al.: DESIGN OF AN IMPLANTABLE SLOT DIPOLE CONFORMAL FLEXIBLE ANTENNA FOR BIOMEDICAL APPLICATIONS 3563

fabricated with a flexible technology, as shown in [18], [19] byone of the coauthors of this paper. At the current level of ouron-going research project, no specific active electronics haveyet been developed. The antenna presented in this paper mightbe slightly large for an immediate implant but it is an importantcontribution to implantable systems because it is flexible, con-formal and completely embedded in biocompatible silicone. Itis, important to first simulate and measure a good antenna struc-ture, such as the one presented in this paper, usable as an inno-vative starting point for future miniaturized design.

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[30] Basic Standard for the Calculation and Measurement of Electromag-netic Field Strength and SAR Related to Human Exposure From RadioBase Stations and Fixed Terminal Stations for Wireless Telecommuni-cation Systems (110MHzŰ 40 GHz), CENELEC EN50383, Sep. 2002.

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[32] Recommended Practice for Determining the Spatial-Peak Specific Ab-sorption Rate (SAR) in the Human Body Due to Wireless Communica-tions Devices: Measurement Techniques, IEEE 1528/D1.2, Apr. 2003.

Maria Lucia Scarpello was born in 1983. Shereceived the B.S. and M.S. degrees in telecommu-nication engineering from the Politecnico di Torino,Torino, Italy, in 2006 and 2008, respectively. She iscurrently working towards the Ph.D. degree at GhentUniversity, Ghent, Belgium.Her research interests include design and char-

acterization of implantable antennas and textileantennas.

Divya Kurup received the B.E. degree in electronicand telecommunication engineering from MumbaiUniversity, Mumbai, India, in 2001 and M.S. degreein telecommunication and network managementfrom Syracuse University, NY, in May 2007.She then joined the Department of Information

Technology (INTEC) of Ghent University in January2008 where she is currently working as a researchassistant in the Wireless and Cable Research group.Her scientific work is focused towards wireless bodyarea networks in particular investigation of in-body

propagation.Ms. Kurup received the Best Student award from Syracuse University for the

academic year 2006–07.

3564 IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 59, NO. 10, OCTOBER 2011

Hendrik Rogier (SM’09) was born in 1971. He re-ceived the electrical engineering and the Ph.D. de-grees from Ghent University, Gent, Belgium, in 1994and in 1999, respectively.He is currently a Postdoctoral Research Fellow of

the Fund for Scientific Research Flanders (FWO-V),Department of Information Technology, GhentUniversity, where he is also Associate Professorwith the Department of Information Technology.From October 2003 to April 2004, he was a VisitingScientist at the Mobile Communications Group

of Vienna University of Technology. He authored and coauthored about 65papers in international journals and about 100 contributions in conferenceproceedings. His current research interests are the analysis of electromagneticwaveguides, electromagnetic simulation techniques applied to electromagneticcompatibility (EMC) and signal integrity (SI) problems, as well as to indoorpropagation and antenna design, and in smart antenna systems for wirelessnetworks.Dr. Rogier was twice awarded the URSI Young Scientist Award, at the 2001

URSI Symposium on Electromagnetic Theory and at the 2002 URSI GeneralAssembly. He is serving as a member of the Editorial Board of IET Science,Measurement Technology and acts as the URSI Commission B representativefor Belgium.

Dries Vande Ginste (M’05) was born in 1977. He re-ceived the M.S. degree and the Ph.D. degree in elec-trical engineering from Ghent University, Gent, Bel-gium, in 2000 and 2005, respectively.From October 2000 until March 2006, he was

with the Department of Information Technology(INTEC), Ghent University, as a Doctoral and Post-doctoral Researcher, where his research focused onfast techniques for the modeling of layered media. InJune and July 2004, he was a Visiting Scientist at theDepartment of Electrical and Computer Engineering,

University of Illinois at Urbana-Champaign (UIUC). From April 2006 to May2007, he was active as a Senior Consultant in a private company, i.e., AppliedLogistics N.V., where he was mainly involved in the modeling of material han-dling systems, feasibility studies, technical-economical evaluations for clients,and where he also had commercial responsibilities. In June 2007, he re-joinedthe Department of Information Technology (INTEC), first as a TechnologyDeveloper in the field of high-frequency technologies for ICT applicationsand since July 2009 as a Postdoctoral Researcher and Lecturer. His currentresearch interests comprise computational electromagnetics, electromagneticcompatibility, and antenna design.

Fabrice Axisa received the M.S. degree in en-gineering and the Ph.D. degree in biomedicalmicrosystem from Ecole Centrale de Lyon (France),in 1996 and 2004, respectively.He worked as an Electronic Designer at ARM

and as a Researcher at INSA Lyon (France) and atIMEC (Belgium). He is currently responsible forthe Microsystem Packaging Laboratory Microsys atthe University of Liege. His main focus is on mi-crosystem development and packaging, biomedicalelectronic system and packaging, and in polymer

based and stretchable electronic system. He is author or coauthor of more than60 articles and 5 patents.

Jan Vanfleteren (M’88) received the Ph.D. degree inelectronic engineering from Ghent University (Bel-gium) in 1987.He is currently a Senior Engineer at the IMEC-

CMST group and is involved in the development ofnovel interconnection, assembly and substrate tech-nologies, especially in wearable electronics technolo-gies. As a project manager for CMST he has a longstanding experience in coordination and cooperationin EC funded projects. In 2004, he was appointedpart time Professor at the Ghent University. He is the

(co)author of over 200 papers in international journals and conferences and heholds 14 patents/patent applications.Dr. Vanfleteren s a member of IMAPS.

Wout Joseph (M’05) was born in Ostend, Belgium,on October 21, 1977. He received the M.Sc. degreein electrical engineering from Ghent University (Bel-gium) in July 2000.From September 2000 to March 2005, he was a

Research Assistant at the Department of InformationTechnology (INTEC) of the same university. Duringthis period, his scientific work was focused on elec-tromagnetic exposure assessment. His research workdealt with measuring and modelling of electromag-netic fields around base stations for mobile commu-

nications related to the health effects of the exposure to electromagnetic radi-ation. This work led to a Ph.D. degree in March 2005. Since April 2005, heis postdoctoral researcher for IBBT-Ugent/INTEC (Interdisciplinary institutefor BroadBand Technology). Since October 2007, he is a Postdoctoral Fellowof the FWO-V (Research Foundation–Flanders). Since October 2009, he is aProfessor in the domain of “experimental characterization of wireless commu-nication systems.” His professional interests are electromagnetic field expo-sure assessment, propagation for wireless communication systems, antennasand calibration. Furthermore, he specializes in wireless performance analysisand quality of experience.

Luc Martens (M’92) was born in Gent, Belgium, onMay 14, 1963. He received the M.Sc. degree in elec-trical engineering from Ghent University (Belgium),in July 1986.From September 1986 to December 1990, he was a

Research Assistant at the Department of InformationTechnology (INTEC) of the same university. Duringthis period, his scientific work was focused on thephysical aspects of hyperthermic cancer therapy. Hisresearchwork dealt with electromagnetic and thermalmodelling and with the development of measurement

systems for that application. This work led to a Ph.D. degree in December 1990.Since January 1991, he is a member of the permanent staff of the InteruniversityMicroElectronics Centre (IMEC), Ghent, and is responsible for the research onexperimental characterization of the physical layer of telecommunication sys-tems at INTEC. His group also studies topics related to the health effects ofwireless communication devices. Since April 1993, he is a Professor in elec-trical applications of electromagnetism at Ghent University.

Gunter Vermeeren was born in Zottegem on March9, 1976. He received the M.Sc. degree in industrialengineering from the KAHO Sint-Lieven (Ghent,Belgium), in July 1998 and the M.Sc. degree in elec-trical engineering from Ghent University (Belgium),in July 2001.From September 2001 to September 2002, he

joined the Research and Development Department ofthe network integrator Telindus (Leuven, Belgium).Since September 2002, he has been a Research Engi-neer in the WiCa group of Prof. Luc Martens. There,

he is involved in several projects in the field of radio frequency dosimetry,electromagnetic exposure, and on-body propagation. His research is in the areaof numerical modeling as well as measurements of electromagnetic fields inthe proximity of humans.