Carl E. Baum has been chosen as the recipient of the 2007 IEEE Electromagnetics Award. A brief biography and remarks from the recipient are provided.

In the above titled paper (ibid., vol. 51, no. 12, pp. 2194-2198, Dec 04), Fig. 3(c) contained incorrect units on vertical axes. A revised paragraph related to Fig. 3 is presented.

The increasing computational demands of finite-difference time-domain simulations for studying optical phenomenon requires codes with very high performance. This paper introduces a new hybrid parallel code using standard MPI and OpenMP technologies. The code is portable to a variety of high performance systems. The transmission of light through an isolated sub-wavelength in an optically thick silver film is outlined as an example application of the code.

Potential for electromagnetic interference (EMI) with cardiac pacemakers in workplaces in electric utilities due to 50- and 60-Hz fields is well known. Only younger employees of electric-utility companies may want to return to their jobs that often entail exposure to such fields. EMI may occur due to exposure to strong external electric fields, magnetic fields, contact currents, and electrostatic discharges (ESD). Numerical modeling of the potential differences produced between the pacemaker electrodes in situ, i.e., in the heterogeneous model of a human body, allows for the evaluation of potential EMI prior to an implantation of the device. Such modeling has been performed and the results are presented and compared for different conditions of potential EMI. As expected, unipolar pacemakers are more susceptible than bipolar devices.

A wideband compact microstrip antenna is designed using the method of moments (MoM) and experimentally evaluated. The VSWR bandwidth of the antenna is more than 90%, while its gain is above 2 dBi. The mechanism of operation of the antenna is also explained. The main advantage of this antenna is its wide impedance bandwidth. The limitation of the design is that the beam direction varies with frequency in the upper part of the bandwidth. This makes the antenna only suitable for wireless communication in a multipath environment. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 99–103, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20913

A modified loop antenna was integrated with EBG structure to form a broadband planar antenna on one of the faces of a telephone handset. Modeling of the complete antenna was performed with the FDTD method. The antenna can operate in four bands allocated for wireless services.

Bone marrow is known to be responsible for leukemia. In order to study the hypothesis relating power-line frequencies electromagnetic fields and childhood leukemia from a subcellular perspective, two models of bone marrow substructures exposed to electric field are computed numerically. A set of cancellous bone data obtained from computed tomography scan is computed using both the finite element method (FEM) and scalar potential finite difference method. A maximum electric field enhancement of 50% is observed. Another model of bone marrow stroma cells is implemented only in FEM using thin film approximation. The transmembrane potential (TMP) change across the gap junctions is found to range from several to over 200 /spl mu/V. The two results suggest that imperceptible contact currents can produce biologically significant TMP change at least in a limited number of bone marrow stroma cells.

Electrostatic discharges (ESDs) occur when two objects at different electric potentials come close enough to arc (spark) across the gap between them. Such discharges may be either single-event or repetitive (e.g., 60 Hz). Some studies have indicated that ESDs may be a causative factor for health effects in electric utility workers. Moreover, a hypothesis has recently been forwarded imperceptible contact currents in the human body may be responsible for health effects, most notably childhood leukemia. Numerical modeling indicates that the electric fields in human tissue resulting from typical contact currents are much greater than those induced from typical exposures to electric and magnetic fields at power line frequencies. Numerical modeling is used here to compute representative spark-discharge dosimetry in a realistic human adult model. The frequency-domain scalar potential finite difference method is applied in conjunction with the Fourier transform to assess electric fields in selected regions and tissues of interest in the body. Electric fields in such tissues as subcutaneous fat (where peripheral nerves may be excited), muscle and bone marrow are of the order of kilovolts per meter in the lower arm. The pulses, however, are of short duration (approximately 100 ns).

Bandwidth enhancement by multiple resonances is a widely used technique for microstrip patch antennas. There are numerous methods to couple multiple resonances. However, such configurations often occupy considerable space and are not always acceptable for integration with other circuitry. For handheld wireless systems, a compact single patch on a moderately thick substrate is preferred. For such an antenna, achieving more than 25 percent bandwidth and moderate gain presents a challenge. We present a single-layer microstrip patch antenna on a relatively thin substrate. The design employs multiple resonances without significantly enlarging the size. It achieves 54% VSWR bandwidth and 40% gain bandwidth for VSWR<2 and G>2 dBi, respectively.

A heterogeneous model of the human body and the scalar potential finite difference method are used to compute electric fields induced in tissue by magnetic field exposures. Two types of coils are considered that simulate exposure to gradient switching fields during magnetic resonance imaging (MRI). These coils producing coronal (y axis) and axial (z axis) magnetic fields have previously been used in experiments with humans. The computed fields can, therefore, be directly compared to human response data. The computed electric fields in subcutaneous fat and skin corresponding to peripheral nerve stimulation (PNS) thresholds in humans in simulated MRI experiments range from 3.8 to 5.8 V/m for the fields exceeded in 0.5% of tissue volume (skin and fat of the torso). The threshold depends on coil type and position along the body, and on the anatomy and resolution of the human body model. The computed values are in agreement with previously established thresholds for neural stimulation.

Contact currents flow when a conducting object such as an animal touches conductive surfaces at different potentials. This completes a path for current flow through the body. These currents provide an additional coupling mechanism between the human body and low-frequency external fields to that due to direct induction effects. Recent research indicates that childhood exposure to residential contact currents may play a role in explaining any possible association between residential magnetic fields and childhood leukemia. To verify this hypothesis, laboratory experiments with rodents are planned. Thus, it is important to understand the relationship between fields induced in rodents and humans. Results from numerical computations are reported here. They are based on high-resolution anatomically based inhomogeneous models of adult and child male humans and male and female rats and mice, for a variety of 60-Hz contact current scenarios. It is hoped that this work will aid in the design of experiments involving rodents and in the interpretation of results as applied to humans. It is found that for geometrically similar models, the induced electric-field scales in an anticipated inverse-square manner with the geometric scaling factor. For dissimilar models, scaling can provide a crude estimate for translating induced field results between species. However, numerical modeling provides the most suitable analysis tool for more accurate estimates.

A hybrid finite-element method (FEM)/method of moments (MoM) technique is employed for specific absorption rate (SAR) calculations in a human phantom in the near field of a typical group special mobile (GSM) base-station antenna. The MoM is used to model the metallic surfaces and wires of the base-station antenna, and the FEM is used to model the heterogeneous human phantom. The advantages of each of these frequency domain techniques are, thus, exploited, leading to a highly efficient and robust numerical method for addressing this type of bioelectromagnetic problem. The basic mathematical formulation of the hybrid technique is presented. This is followed by a discussion of important implementation details-in particular, the linear algebra routines for sparse, complex FEM matrices combined with dense MoM matrices. The implementation is validated by comparing results to MoM (surface equivalence principle implementation) and finite-difference time-domain (FDTD) solutions of human exposure problems. A comparison of the computational efficiency of the different techniques is presented. The FEM/MoM implementation is then used for whole-body and critical-organ SAR calculations in a phantom at different positions in the near field of a base-station antenna. This problem cannot, in general, be solved using the MoM or FDTD due to computational limitations. This paper shows that the specific hybrid FEM/MoM implementation is an efficient numerical tool for accurate assessment of human exposure in the near field of base-station antennas.

Initial experimental verification of confocal microwave imaging for breast tumor detection is described. Simple phantoms, consisting of a PVC pipe and objects representing tumors, are scanned with resistively loaded monopole or horn antennas. Successful reduction of clutter and detection of a variety of two-dimensional objects is demonstrated.

Microwave breast imaging with radar-based techniques has been proposed for breast tumor detection. The feasibility study reported in this paper is designed to evaluate detection and localization of objects in three dimensions (3D). Experimental setups consisting of a PVC pipe (skin) and wood spheres (tumors) are illuminated with a resistively loaded monopole antenna. Improved image reconstruction algorithms are applied to the measured data, and the resulting images demonstrate detection and localization of smaller 3D tumor models.

Heterogeneous model of the human body and scalar potential finite difference method are used to compute electric filed in tissue. This field is compared to the previously obtained thresholds for stimulation of peripheral nerves.

Numerical computations are used to evaluate electric field dosimetry for high-resolution anatomically based inhomogeneous models of a human male child, and male and female rats and mice, under exposure to 60 Hz uniform magnetic field sources of three perpendicular orientations. The goal is to compare the child data to previously computed adult dosimetry and to evaluate the accuracy of linear scaling of organ dosimetry between species. It is expected that this work will aid in the design and interpretation of experiments involving rodents.It is found that child-to-adult and mouse-to-rat organ dosimetry shows the expected linear dependence on the geometric scale factor between models. The comparison between mice and the human child shows that postural and individual organ differences do have significant effects, and that care is required in scaling-based extrapolation of rodent experiment results to humans. However, for unrestrained animals, linear scaling appears to be a reasonable and conservative approach. Most of the rodent organ fields, for at least one field orientation, are greater than those expected from linear scaling.

An active magnetic field sensor consisting of an electrically small loop, two ferrite core transformers, and a balanced amplifier with a low input impedance is suitable for measurements of fields, in a broad range of frequencies, and transients. The sensor provides a flat transfer function from approximately 600 Hz to 200 MHz (3 dB roll-off frequencies) and high-fidelity reproduction of pulses with a risetime of 2 ns. The sensor can be used to measure fields from less than 0.2 mA/m to approximately 0.2 A/m. The sensor has a minimal response to the electric field (at least -20 dB). The sensor's dimensions are 6 cm*6 cm, and the electronic circuitry is contained in a box of approximately 5 cm*8 cm*3 cm. >

Induced electric field and corresponding current density values in various organs of the human body can be computed numerically using a heterogeneous, anatomically representative voxel model. Such computations are available for uniform magnetic fields of various directions with respect to the body. The highest exposure levels occur for non-uniform fields, most often in occupational settings. Various organ induced dosimetric measures of the induced quantities can also be computed, although the associated computational complexity and effort are greater than for uniform fields. A simplified method of estimation of the induced measures is described and validated. The method is based on evaluation of the external (exposure) magnetic flux density in locations corresponding to those occupied by various organs and dosimetry for the uniform fields. Computations of the external fields are relatively simple even for very complex geometries of current-carrying conductors. Computational methods are available for external fields. The external magnetic fields can also be measured. Detailed organ dosimetry is already published. In this contribution, the proposed simplified dosimetry is verified using accurate, numerically computed dosimetry for four non-uniform field exposure scenarios. For most dosimetric measures and organs, the proposed method gives conservative estimates. Only in rare cases when a large organ is in a weak exposure field compared to the whole-body average exposure, the induced dosimetric measures may be underestimated by up to 10%. Another exception is the maximum induced electric field in spatially distributed tissues such as bone marrow, muscle, or skin when a part of the limb is in a very strong magnetic field close to the conductor. However, both of these situations are easily recognizable from the mutual configuration of the human body and the current-carrying conductors. Thus, additional corrections can be applied to the estimates.

Human exposure to external 50/60-Hz electric and magnetic fields induces electric fields within the body. These induced fields can cause interference with implanted pacemakers. In the case of exposure to magnetic fields, the pacemaker leads are subject to induced electromotive forces, with current return paths being provided by the conducting body tissues. Modern computing resources used in conjunction with millimeter-scale human body conductivity models make numerical modeling a viable technique for examining any such interference. In this paper, an existing well-verified scalar-potential finite-difference frequency-domain code is modified to handle thin conducting wires embedded in the body. The effects of each wire can be included numerically by a simple modification to the existing code. Results are computed for two pacemaker lead insertion paths, terminating at either atrial or ventricular electrodes in the heart. Computations are performed for three orthogonal 60-Hz magnetic field orientations. Comparison with simplified estimates from Faraday's law applied directly to extracorporeal loops representing unipolar leads underscores problems associated with this simplified approach. Numerically estimated electromagnetic interference (EMI) levels under the worst case scenarios are about 40 /spl mu/T for atrial electrodes, and 140 /spl mu/T for ventricular electrodes. These methods could also be applied to studying EMI with other implanted devices such as cardiac defibrillators.