The usability of the EMT (Electromagnetic Topology) method is discussed and verified in this paper. The EMT results are compared to the results from a 3D fullwave electromagnetic solver. The electromagnetic wave shows a very fast rise time in the EMP (Electromagnetic Pulse) signal; the SUT (System Under Test) is a simple PCB strip line model. The resistances of the loads attached to each side of the strip line were 1 MΩ and 50 Ω. We then obtained the noise voltages occurring in each load when being penetrated by an EMP. We also discuss the frequency sweeps used to obtain the resonant frequencies of the model. The results agree well with those from the CST Microwave Studio. The EMT method would be more accurate if the dielectric tangent loss and copper loss are considered.

The proposed dipole antenna consists of two printed strips with unequal lengths and is fed by a coplanar strip (CPS) line. As the antenna parameters and port impedance are properly selected, a super wide operating band (|S₁₁|<-10 dB) of 3.5 to 20.0 GHz is realized. Antenna samples were fabricated using standard PCB process. The area of the constructed dipole antenna is 40.0x5.0 mm². The S-parameter measurement was performed via a transition (CPS to double-sided parallel strip line) and transformer (190 to 50 Ohm). The measured fractional bandwidth achieved 139.3% (from 3.4 to 19.0 GHz) as predicted, over which the antenna peak gain is better than 0 dBi.

In three-dimensional space, the hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) method is weakly conditionally stable, only determined by two space-discretizations, which is very useful for problems with fine structures in one direction. Its numerical dispersion errors with nonuniform cells are discussed and compared in this paper. To enlarge the applicable field of the HIE-FDTD method to open space, the absorbing boundary conditions (ABCs) for this method are also introduced and applied. Two microstrip filters with fine scale structures in one direction are solved by the HIE-FDTD method. Conventional FDTD method and alternating-direction implicit FDTD (ADI-FDTD) method are also used for comparing. Results analyzed by the HIE-FDTD method agree well with those from conventional FDTD, and the required central process unit (CPU) time is much less than that of the ADI-FDTD method.

This study experimentally demonstrates a broadband (20%) superluminality in a Fabry-Pérot-like interferometer implemented on a waveguide system. A narrow wave packet propagating with an efective group velocity of 5.29 ^+4.28 _-1.70 c without distortion was observed. The underlying mechanism is attributed to the multiple-reflection interference and the modal effect, which provide an approach for controlling the wave characteristics through manipulating the geometry of the system. Besides, the criteria of the renowned generalized Hartman effect are explicitly clarified.

The preparation of good navigational synthetic aperture radar (SAR) reference image is critical to the SAR scene matching aided navigation system, especially for complex terrain. However, few papers discuss the problem, and almost none of the methods proposed by them are fully automatic. Based on the practical requirements, a fully automated method of SAR reference image preparation is introduced. Firstly, a number of distinctive control points (CP) in the simulated SAR image is detected based on a method of image segmentation and clustering. Then, the corresponding tie-points in the real SAR image are searched based on local similarity by means of template matching. To improve the accuracy of CP, a method for segmentation threshold calculation, outlier screening and sub-pixel location computation is presented. Finally, the real SAR image is warped to the simulated one, and then projected to the frame of digital elevation model (DEM) by the polynomial mapping function. Experimental results on real data sets demonstrate the accuracy and efficiency of the proposed method.

The paper studies boundary conditions in transformation-optics cloaking for two and three dimensional electromagnetic waves. Implicit boundary conditions for these two cases are derived, no matter if the source is placed in the interior or exterior of the cloak layer. More importantly, the two implicit boundary conditions are derived without solving Mie scattering problems, and these conditions are characteristics of the clock-air interface. In particular, the implicit boundary condition for two-dimensional electromagnetic wave case is reported for the first time. In addition, a sensor can be cloaked in two-dimensional electromagnetic waves, i.e., waves can penetrate into the interior of the cloak layer without exterior scattering.

A novel 12 GHz VCO designed and fabricated in a 0.18 μm SiGe BiCMOS technology is presented. Strongly magnetic coupled dual LC tanks with fixed and tunable capacitive elements are introduced to extend tuning range and improve phase noise. By hybrid using of varactor tuning, loaded transformer tuning and switched capacitor tuning, the proposed VCO achieves a wide tuning range of 4.3 GHz (36%) and output power of -9 dBm with only 4.5 mW power consumption and only 0.17 mm² chip area.

In this paper, a four-element microstrip antenna array is presented. The array is composed of Wilkinson power dividers which act as feed network along with Dolph-Chebyshev distribution and four-identical patch antenna elements. The array elements are properly designed to have a compact size and constant gain against frequency. The simulated results show good agreement with the measured results for the fabricated antenna array. Measurement shows that the array has a peak gain of more than 12 dBi with side-lobe level of -15 dB at 6 GHz. These characteristics make the antenna array suitable for UWB directional uses.

The success of wireless technologies could paradoxically leads to a collapse in their performance: the interference between adjacent networks and the attacks done by users from outside the expected coverage limits are two important enemies to the well function of the networks. The proposal of this paper is simple but efficient: the use of vegetation barriers to create shadowing areas with excess attenuations in the edge of the service area, in order to reduce the coverage distance of each wireless node, reducing the possible interference to other networks as well as improving security aspects by minimizing the signal strength outside the service area.

We present a parallel implementation of the multilevel fast multipole algorithm (MLFMA) for fast and accurate solutions of electromagnetics problems involving homogeneous objects with diverse material properties. Problems are formulated rigorously with the electric and magnetic current combined-field integral equation~(JMCFIE) and solved iteratively using MLFMA parallelized with the hierarchical partitioning strategy. Accuracy and efficiency of the resulting implementation are demonstrated on canonical problems involving perfectly conducting, lossless dielectric, lossy dielectric, and double-negative spheres.

This paper deals with an analytical solution of the time domain Pocklington equation for a straight thin wire of finite length, buried in a lossy half-space and excited via the electromagnetic pulse (EMP) excitation. Presence of the earth-air interface is taken into account via the simplified reflection coefficient arising from the Modified Image Theory (MIT). The analytical solution is carried out using the Laplace transform and the Cauchy residue theorem. The EMP excitation is treated via numerical convolution. The obtained analytical results are compared to those calculated using the numerical solution of the frequency domain Pocklington equation combined with the Inverse Fast Fourier Transform (IFFT).

During Magnetic Resonance Imaging (MRI), the presence of an implant such as a Deep Brain Stimulation (DBS) lead in a patient's body can pose a significant risk. This is due to the fact that the MR radiofrequency (RF) field can achieve a very high strength around the DBS electrodes. Thus the specific absorption rate (SAR), which is proportional to the square of the magnitude of the RF electric field, can have a very high concentration in the near-field region of the electrodes. The resulting tissue heating can reach dangerous levels. The degree of heating depends on the level of SAR concentration. The effects can be severe, leading to tissue ablation and brain damage, and significant safety concerns arise whenever a patient with an implanted DBS lead is exposed to MR scanning. In this paper, SAR, electric field, and temperature rise distributions have been found around actual DBS electrodes. The magnitude and spatial distribution of the induced temperature rises are found to be a function of the length and structure of the lead device, tissue properties and the MR stimulation parameters.

On the basis of the extended Huygens-Fresnel principle, the cross-spectral density matrix (CSDM) of partially coherent Gaussian Schell-model (GSM) beams in the slant atmospheric turbulence is derived. Given that the light emitted from a transmitter is elliptically polarized light, the degree of polarization (DoP) of the partially coherent GSM beams is represented by Stokes parameters expressed by the elements of the CSDM. The expressions of the orientation angle, polarized light intensity in the major axis are derived and the numerical results are presented. Depolarization theory is studied using a Mueller matrix and the depolarization index (DI) is obtained to describe the depolarized state of the partially coherent GSM beams propagating in the slant atmospheric turbulence. Results show that the DOP and DI of the beam tend to their initial value in the long-range propagation.

Long term radio frequency electromagnetic field (RF EMF) exposures due to Global System for Mobile communication (GSM) frequencies were investigated in this study. 158 Swiss Albino mice in unrestrained conditions were used as surrogate and divided into four groups. The average peak field strength generated and measured inside the cages placed at a far field from the antennas is 0.6x10^-3 mW/cm², and the specific absorption rate at 0.9 GHz and 1.8 GHz is 2.33x10^-3 W/kg and 1.97x10^-4 W/kg, respectively. Three samples of the mice chosen at random each from sham and exposed groups in week 4 and subsequently biweekly basis were taken for haematology and histopathology tests. The complete blood count result shows that haematological parameters of both the sham exposed and exposed mice were within the normal range of mice in the control group. A statistical analysis was conducted to determine whether differences observed between the experimental groups were significant. The histopathology examination on some internal organs shows that spleen and bone marrow of the mice were normal for all the three experimental groups, while a sign of tissue degeneration and inflammations were observed after 8 weeks of exposure on the brain, liver and lungs of the mice in the exposed groups. These signs increase in severity with prolonged exposure.

Next generation communication system, such as Long Term Evolution Advanced (LTE-A), has the advantages of high transmission rate, wide bandwidth and better bandwidth utilization in high mobility environments. However, in such a kind of system when users are distributed sparsely in the base station coverage range the spectrum efficiency becomes worse. The emergence of new technologies such as the coordination among based stations makes the utilization of system bandwidth more efficient. The technology of coordination among base stations has other merits such as reducing noise interference, increasing receiving diversity, improving the system receiving gain, etc. In this paper, the system spectrum utilization and its associated efficiency will be investigated when the scheme of coordination among base stations is implemented.

In this paper, a novel Wavelet-Galerkin Method (WGM) is presented to model the radio-wave propagation in tropospheric ducts. Galerkin method, with Daubechies scaling functions, is used to discretize the height operator. Later, a marching algorithm is developed using Crank-Nicolson (CN) method. A new ``fictitious domain method'' is also developed for parabolic wave equation to incorporate the impedance boundary conditions in WGM. In the end, results are compared with those from Advance Refractive Effects Prediction System (AREPS). Results show that the wavelet based methods are indeed feasible to model the radio wave propagation in troposphere as accurately as AREPS and proposed method can be a good alternative to other conventional methods.

This paper proposes a new design of coplanar waveguide dual-band bandstop filter (DBBSF) with center frequencies at 1.8 GHz and 2.8 GHz. A lumped element model of four series-connected parallel LC resonators are derived, then implemented using compact CPW resonators patterned in the center conductor. The measured and simulated responses are in good agreement which validates the design.

The dependence of reflectivity on inhomogeneous plasma density for one dimensional plasma photonic crystal is presented. The exponential varying and linear varying plasma density profiles have been chosen in such a way that the volume average permittivity remains constant. The transfer matrix method is used to derive the dispersion relation and reflectivity of the proposed structures by employing the continuity conditions of electric fields and its derivatives on the interface. The exponential varying plasma density profile gives high reflectivity than the linear varying plasma density profile in all considered cases. Also the exponential varying plasma density profile shows perfect reflection in considered volume average permittivity. This profile may be used in sensor applications or in plasma functional devices.

With the increases of the module integration density and complexity in electrical and power electronic systems, serious problems related to electromagnetic interference (EMI) and electromagnetic compatibility (EMC) can occur. For the safety, these disturbing effects must be considered during the electronic equipment design process. One of the concerns on EMC problems is induced by unintentional near-field (NF) radiations. The modeling and measurement of EM NF radiations is one of the bottlenecks which must be overcome by electronic engineers. To predict the unwanted different misbehaviors caused by the EM radiation, NF test benches for the reconstitution of scanning maps at some millimeters of electrical/electronic circuits under test were developed at the IRSEEM laboratory. Due to the difficulty of the design with commercial simulators, the prediction of EM NF emitted by active electronic systems which are usually based on the use of transistors necessitates more relevant and reliable analysis techniques. For this reason, the main focus of this article is on the experimental analysis of EM NF radiated by an MOSFET transistor with changing electrical parameters. Descriptions of the experimental test bench for the EM map scan of transistors radiation are provided. This experimental setup allows not only to detect the EM NF emission but also to analyze the influence of the excitation signal parameters as the cyclic ratio. It is found that the magnetic radiation is maximal when the cyclic ratio is close to 50%. In the future, In the future, the technique introduced in this article can be used to evaluate the EM radiation of embedded electronic/electrical devices in order to improve the safety and security of electronic systems.

In this work, we consider a waveguide composed of two periodic, perfectly conducting, one-dimensional rough surfaces. This periodic system has a band structure similar in some aspects to a one-dimensional photonic crystal. However, our system has some additional interesting features. We calculate the band structure and the reflectivity of a corresponding finite waveguide. We found that the variation of the roughness amplitude and the relative phases allow to control at a certain degree the band structure of the system. Particularly, wide gaps can be obtained. It is even possible to obtain discrete modes for some frequency range and then the periodic waveguide acts as an unimodal filter. The system considered constitutes itself a photonic crystal whose band structure corresponds in many ways to a conventional photonic crystal but using just a single material. The key properties of this system are that it really constitutes a waveguide whose optical response is similar to that of a one-dimensional photonic crystal.