This paper discusses the characterization of landmine by using the electromagnetic induction technique (EMI). The proposed approach is based on the identification of the physical and geometrical properties of a landmine, from the sensor response. But in such an identification, the inverse problem is unavoidable. At first, we begin by simulating the landmine signature by solving a direct problem using the finite element method which constitutes the direct model. After that, we determine the landmine characteristics by using an inverse model based on a cost function optimization. This model is based on an iterative process which coupling nite element analysis and Particles Swarm Optimization (PSO). In this step, we apply two PSO techniques: the Standard PSO (SPSO) and the Improved PSO (IPSO), and discuss the problem of local minima of the cost function. The proposed iterative model is applied to determine the conductivity, geometry, and depth of metallic landmine from its signature measured by EMI. The numerical solution gives good results for the identification of landmine.

In this work, we propose a merged coil structure for wireless chip-to-chip communication technology. Using the proposed coil structure, the chip size can be reduced, and the transmitted power can be improved by approximately 5 dB compared to typical coil structure. To verify the feasibility of the coil, an electromagnetic simulation and a schematic simulation are performed. The coil was implemented using 50-nm digital CMOS technology. From the experimental results, the feasibility was proved.

An ultra-wideband (UWB) antenna with a novel multi-layer frequency selective surface (FSS) reflector is presented. A significant enhancement in the gain has been achieved in a low profile design while maintaining the excellent impedance bandwidth of the UWB antenna. The average peak gain of the antenna has been increased from 4 dBi to 9.3 dBi as a consequence of the use of the FSS reflector. More importantly the gain variation within the frequency range from 3 GHz to 15 GHz is only ±0.5 dB. This is a significant improvement from ±2 dB gain variation of the UWB slot antenna without the reflector. This optimized FSS reflector provides the exibility of mounting a planar antenna close to conducting bodies, including screens and cases.

A method to control the transmission zero of TE_01δ mode dielectric-resonator (DR) filters for wireless base stations is proposed. Instead of using folder structures, dedicated coupling probes, or extra cavities, as required by conventional techniques, transmission zeros are realized. The feeding probes, extended along ring dielectric resonators, are used to excite the TE_01δ mode and introduce transmission zeros. By rotating the angle of feeding position, transmission zeros can be shifted to the lower or the upper stopband. Thus, TE_01δ mode dielectric resonator filters with quasi-elliptic responses are realized with only iris coupling components. Based on this method, fourth-order inline TE_01δ mode DR filters with different responses are designed and fabricated. Measured results confirm the predicted performance.

A compact waveguide(CPW)-fed dual-frequency planar monopole antenna is proposed, which can excite two modes.The antenna is composed of a epsilon negative (ENG) meta-structured transmission line (MTL) unit cell and a monopole. The first resonance is zeroth-order mode,which is described using dispersion relation of ENG MTL based on Bloch and Floquet and designed on a CPW single layer where vias are not required. And the second is electromagnetically coupled monopolar mode. The zeroth-order resonant phenomenon is employed to reduce the antenna size. To design and analyze the proposed antenna, the circuit simulation of the ENG MTL unit resonator is executed by the equivalent circuit, and the results are compared with those of full wave simulation and experiment. The results show that the presented antenna reasonable radiation characteristics of bandwidth gain and size, verified by a commercial EM simulation software HFSS11, and is suitable for compact dual-frequency antenna. Then the antenna is fabricated and measured. The realized antenna has a compact size of 0.288λ₀ x 0.199λ₀ x 0.011λ₀(25.1mm x 17.4 mm x 1 mm) at 2.43 GHz. Simulated and experimentally measured results show that the proposed antenna can operate at 2.41(2.43) GHz and 4.11(4.14) GHz bands, respectively. Good agreement between the simulated and measured results is obtained.

This paper presents two simple analytical models of the switched reluctance motor. The first model is constructed on two flux linkage-current characteristics, the aligned position one calculated via finite element analysis (FEA), and the unaligned position characteristic calculated by using motor geometry data. The second model is based on three flux linkage-current characteristics, the aligned, unaligned and average one, obtained by employing the FEA. In both cases the direct and inverse models are defined. The models consider the core nonlinearity and the influence of the rotor position on the motor behavior. The estimated magnetizing and torque characteristics are compared with that calculated via two dimensions FEA for a switched reluctance motor (SRM) sample and with the test bench obtained ones. The merits and the drawbacks of the models are evinced.

An impedance-permeability (Z-μ_r) resonance phenomenon is firstly founded and numerically demonstrated when electromagnetic metamaterials with negative permeability are firstly introduced into inductance coil. Numerical results reveal that the impedance-permeability relationship exhibits an extraordinary self-resonant phenomenon at a certain negative value of relative permeability, which is related to the dimensions of the core but nearly independent to the coil size. Such a mechanism is proposed to increase the sensitivity of eddy current (EC) sensors up to about 270 times, offering a new method to greatly improve the sensitivity of EC sensors and the spatial resolution with micrometer scale.

Low loss circular birefringence is found in three-dimensional artificial triple helices. High values of chirality index are generated. Within the transmission bandwidth, there is a significant difference in the refractive index value of the right- and left- polarized waves. The outgoing waves from a wedge structure designed from these triple helices are proved to split with a wide angle. The wave polarizations agree with earlier simulation results.

This paper presents a design of perforated nanoantenna reflectarray. The use of metallic nanostructures made of Silver and/or Gold at appropriate wavelength cause fascinating unusual electromagnetic effects. Reflectarray consists of an array of unit cell made from Silver is investigated. The effect of the number of perforated holes in the unit cell configurations is investigated for proper reflection coefficient phase compensation. A linearly polarized pyramidal nano-horn is used to feed the perforated nanoantenna reflectarray. The radiation characteristics of 9 × 9 perforated nanoantenna reflectarray are illustrated. A high gain of 20.5 dB is obtained at the designed frequency of 735 THz. A comparison between solid Silver sheet with no perforation holes and the proposed perforated reflectarray is explained.

In this paper an in-depth parametric analysis of shielding effectiveness obtained when using ferromagnetic or conductive screens to mitigate the field generated by duct banks is presented. Due to the need of a case-by-case approach, all the simulations, performed by a finite element software (GetDp), are applied to a case study composed by 9 (3x3) ducts, with six of them including high voltage single-core cables and the three left empty for eventual future expansion. Two shielding geometries are tested: horizontal and U-reverse, changing in each one the main parameters: width, thickness, clearance to conductors, etc. Moreover, the conductors are grouped in two balanced in-phase three-phase circuits arranged in three configurations: vertical, horizontal and triangular. The mutual phase ordering of both circuits is the one that minimizes the field, so no further field reduction can be obtained by simple methods. The power losses and cost of different shielding solutions are also presented, including the effect of adding a third circuit if required.

In this paper, the applications of chiral layers and metamaterials as radar absorbing materials are investigated. A perfect electric conductor plate covered by a chiral metamaterial is considered and after the formulation of the problem, reflection of the structure under an oblique plane wave incidence of arbitrary polarization is investigated. Then several examples of the applications of chiral layers in nondispersive, dispersive, and chiral nihility conditions are provided to design of zero reflection coatings. Finally, application of chiral metamaterial structures as microwave absorbers is discussed. In some of the provided examples, the method of genetic algorithm is used to optimize chiral coatings for the minimization of co- and cross reflected power.

In this paper, we present an efficient Artificial Neural Network (ANN)-based model to estimate both azimuth and elevation arrival angles of a signal source. To achieve this goal, the ANN model is constructed using measurement data obtained by a rectangular antenna array in the space-frequency domain. Unlike classical super-resolution algorithms such as 2D MUSIC, the proposed model is capable to account for imperfections of measurement equipment as well as mutual couplings between array elements. The neural model has been verified for several angular positions and frequencies. It is shown that use of ANN model to estimate angular positions of a signal source yields more accurate results when compared to 2D MUSIC. Moreover, the neural model significantly outperforms 2D MUSIC in terms of speed of computation.

It is potentially useful to perform target identification using micro-Doppler features because they contain information on the geometrical structure of the target. In this paper, the m-D effect of the rotationally symmetric ballistic target (BT) is analyzed which reveals that the m-D is not a form of sinusoidal modulation due to the sliding-type scattering. Inspired by the extended Hough transform (EHT), a method to extract all the six parameters of the BT is proposed. The m-D effect and the performance of feature extraction algorithm are demonstrated by the measured data in a microwave anechoic chamber.

The theory and design of a new family of multifrequency monopole antennas by smartly loading a set of complementary metamaterial transmission line (CMTL) unit cells are investigated. The distributed CMTL elements, epsilon negative (ENG) or double negative (DNG) through incorporating additional capacitive gaps, contain a Koch-shaped extended complementary single split ring resonator pair (K-ECSSRRP) etched on the signal strip. The K-ECSSRRP features dual-shunt branches in the equivalent circuit model, rendering a distinguished resonator with dual zeroth-order resonant (ZOR) modes. By smartly controlling the element layout and loading different numbers of unit cells, ten antennas covering different communication standards (GSM1800, UMTS, Bluetooth, DMB and WIMAX) are designed and four of them are fabricated and measured. At most of operating frequencies, the antennas exhibit impedance matching better than -10 dB and normal monopolar radiation patterns. Numerical and experimental results both confirm that the single-cell or dual-cell ENG and DNG CMTL-loaded monopoles exhibit almost identical dual ZOR modes. Moreover, the loaded elements also contribute to the radiation, which is the major advantage of this prescription over previous lumped-element loadings. These antennas are compact and the multiple operating bands can be arbitrarily engineered, enabling an alternative and easy avenue toward monopoles with multifunction and high integration.

The need to find ways to effectively utilize the large quantities of agricultural waste that are produced is indicative of the huge potential associated with producing an alternative pyramidal microwave absorber for anechoic chamber-testing applications. We propose the development of a pyramidal microwave absorber that can use sugar cane bagasse (SCB), a byproduct from the production and processing of sugar cane, as the absorbent. In this paper, we report the results of our use of dielectric probe measurement to determine the dielectric constant and loss tangent of SCB. These values were used to model and simulate an SCB pyramidal microwave absorber in Computer Simulation Technology's (CST's) Microwave Studio. This absorber was operated in the microwave frequency range between 0.1 GHz and 20.0 GHz.

In this paper, the network expression is proposed for finite-length multiple transmission lines in arbitrary directions. Crosstalk between two bent transmission lines is analyzed using the proposed approach as an example of application. The resultant network function is obtained in the form of an ABCD matrix for two bent transmission lines is obtained. The validity of the proposed approach was confirmed by comparing experimental results with computed results and those simulated by a commercial electromagnetic solver for some bent-line models.

This paper presents a novel dielectric resonator antenna (DRA) for multiband mobile terminal communication applications. A variation of circular sector dielectric resonator antenna partially coated with metal on its surface is used as the main radiating element. The DRA is fed by a monopole slot-coupled 50-Ω microstrip feed line, which can also provide another radiation mode. By thorough design, the antenna achieves the desired 470-960 MHz band for DVB-H/GSM850/900 operation and 1710-1990 MHz band for DCS/PCS operation. The dimensions of the antenna presented are λ₀/17 x λ₀/9 x λ₀/35 at 470 MHz with appropriate dielectric permittivity ^{ε_r = 16}.

This paper deals with the dielectric loaded Exponentially Tapered Slot (ETS) antenna needed for ultra-high-speed, high-capacity wireless communication systems which work at 60 GHz and illustrates its specifications and requirements. The antenna in such system requires high gain, high-efficient and high performance design specifications. The ETS antenna and the loaded dielectric are integrated using the same single substrate resulting in easy fabrication and low cost. The ETS antenna with rectangular and elliptical shaped loaded dielectrics were designed and fabricated. These antennas have high gain and wider beamwidth in both E-plane and H-plane. The proposed antenna design is simulated using 3D electromagnetic software CST Microwave Studio and the comparison is made with Ansys HFSS to validate the design procedure. The results obtained from the simulations and the measurements are in good agreement.

An APF (All-Pass Filter) delay module in which eight single-ring resonators are serially cascaded is designed and fabricated. The polymer waveguide used for the realization of the APF delay module is a buried structure whose core width and height are 1.5μm. The core and cladding index are 1.51 and 1.378, respectively, which corresponds to the relative index difference of 8%. In order to use a thermo-optic effect of polymer materials, electrodes are evaporated above the ring resonator to provide heating currents. The time delay is measured to be about 50 ps when 2 rings are in resonance, and about 105 ps and 150 ps, respectively, when 4 and 6 rings of APF are in resonance, respectively. When all of 8 rings are in resonance, the delay is measured to be about 200 ps.

A broadband zeroth-order resonant (ZOR) antenna based on asymmetric coplanar waveguide (ACPW) is presented. By adopting the epsilon negative transmission line (ENG-TL), a zeroth-order resonance mode can be achieved. We propose an asymmetric coplanar waveguide structure which offers the design freedom to realize the broadband ZOR antenna, where the antenna's bandwidth is characterized by an equivalent circuit parameters. The antenna has the compact unit cell dimensions of 5×13.8 mm². The measured results show that the operating bandwidth is about 1050 MHz (1.90-2.95 GHz), and the peak gain and radiation efficiency are 2.46 dBi and 91% at 2.3 GHz. Owing to the characteristics of broad bandwidth, high efficiency, omnidirectional radiation, and easy manufacturing, the proposed ACPW ZOR antenna is very suitable for modern wireless communication systems (UMTS, WLAN, WIMAX, LTE).