Compared with MPI, OpenMP provides us an easy way to parallelize the multilevel fast multipole algorithm (MLFMA) on shared-memory systems. However, the implementation of OpenMP parallelization has many pitfalls because different parts of the MLFMA have distinct numerical characteristics due to its complicated algorithm structure. These pitfalls often cause very low efficiency, especially when many threads are employed. Through an in-depth investigation on these pitfalls with analysis and numerical experiments, we propose an efficient OpenMP parallel MLFMA. Three strategies are proposed in the parallelization, including: 1) the choice of OpenMP schedule manners; 2) loop reorganization for far-field interaction in the MLFMA; 3) determination of a transition level. Numerical experiments on large scale targets show the proposed OpenMP parallel scheme can perform as efficiently as the MPI counterpart, and much more efficiently than the straightforward OpenMP parallel one.

This paper is devoted on the characterization method of RF/digital PCB interconnections for the prediction of the high-speed signal transient responses. The introduced method is based on the use of the interconnection line RLCG-model. Theoretical formulae enabling the extraction of the electrical per-unit length parameters R, L, C and G in function of the interconnection line physical characteristics (width, length, metal conductivity, dielectric permittivity ...) are established. Then, by considering the second order approximation of the interconnection RLCG-model transfer matrix, the calculation process of the transient responses from the interconnection system transfer function is originally established. To demonstrate the relevance of the proposed model, microwave-digital interconnection structure comprised of millimetre microstrip line driven and loaded by logic gates which are respectively modelled by their input and output impedances was considered. Then, comparisons between the SPICE-computation results and those obtained from the proposed analytical model implemented in Matlab were made. As results, by considering a periodical square microwave-digital excitation signal with 2 Gbits/s rate, transient responses which are very well-correlated to the SPICE-results and showing the degradation of the tested signal fidelity are observed. The numerical computations confirm that the proposed modelling method enables also to evaluate accurately the transient signal parameters as the rise-/fall-times and the 50% propagation delay in very less computation time. For this reason, this analytical-numerical modelling method is potentially interesting for the analysis of the signal integrity which propagates in the high-speed complex interconnection systems as the clock tree distribution networks. In the continuation of this work, we would like to apply the proposed modelling process for the enhancement of signal quality degraded by the RF/digital circuit board interconnection where the signal delays and losses became considerably critical.

A highly miniaturized simplified composite right/left handed (SCRLH) mushroom zeroth-order resonator (MZOR) is proposed for bandpass filter (BPF) design. By introducing the U-slot etched around the metallic via (UEAV), more flexible selection of the shunt inductance value can be achieved compared with the original one. As the length of UEAV increased, zeroth-order resonant frequency of the MZOR decreased, even 88% size reduction can be achieved. Finally, a bandpass filter based on the proposed MZOR is designed, fabricated and measured. The simulated and measured results are presented and good agreement is obtained.

A novel bandwidth enhancement design of planar F-shaped dipole antenna for RFID tag is proposed. With the use of two parasitic strips inset along the closed loop of the input IC chip in this proposed tag antenna, a new resonant mode close to 900 MHz band is excited to enhance the operating bandwidth. The obtained impedance bandwidth across the operating band can reach about 104 MHz for UHF band. With omni-directional reading pattern, the measured reading distance is about 2.8 m as the tag antenna mounted on the glass object.

The paper describes the modelling of the average rainfall rate distribution measured at different locations in South Africa. There are three major aspects this paper addresses: to develop a rainfall rate model based on the maximum likelihood method (ML); to develop contour maps based on rainfall rate at 0.01% percentage of exceedence; and re-classification of the ITU-R and Crane rain zones for the Southern Africa region. The work presented is based on five-minute rainfall data converted to one-minute equivalent using a newly proposed hybrid method. The results are mapped and compared with conventional models such as the ITU-R model, Rice-Holmberg, Moupfouma and Crane models. The proposed rainfall rate models are compared and evaluated using root mean square and chi-square (χ²) statistics. Then re-classification of the rain zone using ITU-R and Crane designations is suggested for easy integration with existing radio planning tools. The rainfall rate contour maps at 0.01% percentage of exceedence are then developed for South Africa and its surrounding islands.

We present an optical model based on Green function to investigate the effect of using Single Wall Carbon Nanotube (SWCNT) as anode for infrared light emitting devices (IR QD-LEDs). To the best of our knowledge there is no report in using SWCNT as anode in IR QD-LEDs. We have studied the emitted power distribution among the different optical modes (air, substrate, anode/organics, and surface plasmon modes (SP)), angular intensity distribution, and the emission spectral characteristics. We have found that the light outcoupling efficiency of IR QD-LEDs based on SWCNT as anode was increased nearly by a factor of 4 relative to that one based on indium-tin oxide (ITO). We also investigated the effect of using different cathode materials on the optical characteristics of IR QD-LEDs.

To investigate the effects of pulsed electromagnetic field (PEMF) with high electric field intensity on bone formation in murine osteoblast-like MC3T3-E1 cells, proliferation, alkaline phosphotase (ALP) activity, mineralized nodule formation, Collagen Type I (COL-I) and core-binding factor (Cbf)a1 mRNA expression, and bone morphogenetic protein (BMP)2/4 and mothers against decapentaplegic (Smad)1/5/8 protein expression were examined in cultured MC3T3-E1 cells after exposure to PEMF at the field intensities of 0kV/m, 50kV/m or 400kV/m for 400 consecutive pulses daily for 7 consecutive days. After 50 kV/m of PEMF exposure, none of the above parameters of MC3T3-E1 cells changed significantly when compared to the control groups. However, the proliferation, ALP activity and mineralized nodule formation of MC3T3-E1 cells in 400 kV/m PEMF exposure groups decreased significantly although COL-I and Cbfa1 mRNA expression and BMP2/4 and Smad1/5/8 protein expression did not change. The PEMF we used at high electric field intensity suppressed proliferation, differentiation and mineralization of MC3T3-E1 cells in culture and appeared to be harmful for bone formation.

In this paper, a reduced size dual-frequency Wilkinson power divider (WPD) is presented. The miniaturization is accomplished by using two sections of non-uniform transmission line transformers in place of the two uniform sections in the conventional dual-frequency WPD. Two isolation resistors are also used to achieve good isolation between the output ports. Optimization is carried out based on simple uniform transmission line theory. For verification purposes, a dual-frequency WPD operating at 0.5 GHz and 1 GHz is designed, analyzed and fabricated.

In this paper, a parametric electromagnetic radiated emission model has been explored. Several mathematical improvements with respect to its extraction and computational performance have been deployed. The model, represented with an array of radiating electric dipoles, predicts the electromagnetic emission of components and systems. Core-level changes have been made in order to extract the model parameters: the dipole positions, their orientations and currents, and the effective relative permittivity from near-field measurements. Thresholding and windowing techniques are used to detect and optimize dipole positions, directly from the field data. A fast and memory efficient two-level optimization algorithm based on the Levenberg-Marquardt non-linear least squares technique is implemented for parametric extraction. All the constraints of the previous model have been overcome and the system is validated for mono-substrate and multi-substrate devices from measurements and/or simulations, with promising results. A tremendous improvement in modeling capability and performance has been obtained when compared with that of its erstwhile counterpart.

This work presents a two-dimensional (2D) subgrid technology for the geodesic finite different time-domain (FDTD) algorithm, which is applied to solve global extremely low frequency (ELF) electromagnetic EM wave propagation problems in the Earth-ionosphere system. The new technology provides arbitrarily locale resolution to study finer structure without disturb the global grid structure. Combined with the subgrid technique, the new geodesic FDTD algorithm can solve EM propagation problems in specific locale regions without extra computational burden. Based on the original geodesic FDTD formulations, the 2D subgrid technique is developed, and its computational stable relation is derived and analyzed. Then, possible three-dimensional (3D) subgrid structure is proposed. Finally, potential applications for the subgrid technique are suggested.

This paper focuses on the noise and vibrations of induction motors. It proposes an analytical method to distinguish the phenomenon responsible on the magnetic noise, especially the toothing and the saturation. A 3-speed 3-phase induction motor, which works sporadically at low speed for hoisting, serve as a support for experiments. Its acoustic noise during this operating mode is really important. A complete diagnosis is proposed with a 2D analytical model. The approach is progressive and it shows analytically that magnetic saturation is mainly responsible on these noise level. Then, the presented developments makes it possible to identify, in simple way, the noise components due to the both magnetic saturation and toothing effects.

A simple approach is proposed for retrieving the forward and backward wave impedances of lossless and lossy bianisotropic metamaterials. Compared with other methods in the literature, its main advantage is that forward and backward wave impedances can be uniquely and noniteratively extracted. It has been validated for both lossless and lossy bianisotropic metamaterials by performing a numerical analysis. The proposed approach can be applied for checking whether the metamaterial structure shows the bianisotropic property by monitoring forward and backward wave impedances, since the forward and backward wave impedances of a metamaterial structure depend on different polarizations of the incident wave.

In this paper, the design method of a quadruple-band rejection ultra-wideband (UWB) antenna with three co-directional complementary split ring resonators (CSRRs) is proposed. Within the design step, individual antennas corresponding to each rejection band is first designed, and then a finalized structure is determined by assembling these individual antennas altogether. The shape of the final antenna achieves both the impedance matching of ultra-wideband and the respective resonances at four rejection bands. Here, the mutual coupling among the band rejection elements is minimized, and the placement of the resonators is optimized. The fabricated antenna is compact enough to be integrated into the UWB system, and also the measured results show the validity of the proposed design strategy.

This paper deals with passive microwave imaging for fire detection by means of a single-channel ground-based radiometer. The simulation of images sensed in the presence of fire spots under different environmental and operative conditions will be presented. We will refer to a low-cost ground-based radiometer operating at 12.65 GHz. Scenarios with fires where visible and IR sensors are not useful with respect to a microwave imager will be investigated in deep, such as in the presence of vegetation canopy optically masking fire sources and smoke plumes in the early stage. These simulations will assess limits and capabilities of microwave imaging for the identification of little fires masked by forest areas.

A composite medium containing perfectly conducting short needles can have a range of frequency for which the real part of the effective permittivity of the composite is negative. Such a range of frequency can be taken as negative bandwidth. This negative bandwidth for a composite medium is dependent upon parameters like positioning, orientation, length and needle density of short needles. Effects of random errors in positioning and orientation of short needles upon the ensemble averaged effective permittivity are analyzed. It is studied theoretically that increasing error in positioning and orientation of short needles reduces negative bandwidth.

The mutual correlation function of the phase fluctuations of scattered ordinary and extraordinary waves by the magnetized plasma slab with electron density fluctuations and the variance of the Faraday angle is calculated by the perturbation method. Analytical expression of broadening of the spatial spectrum of scattered radiation is obtained for arbitrary fluctuation spectrum. Numerical calculations are carried out for the anisotropic Gaussian fluctuation spectrum at different anisotropy factor and the angle of inclination of prolate irregularities with respect to the external magnetic field. Isolines of the normalized root mean square deviation of the Faraday angle nonlinearly depends on the angle of inclination of prolate irregularities and increases in proportion to the anisotropy factor; two receiving antennas are located in orthogonal planes. It is shown that the broadening of the spatial spectrum of scattered electromagnetic waves by turbulent magnetized plasma slab in the principle plane (location of an external magnetic field) is less than in the perpendicular one.

We present a new accurate node's renumbering method for minimizing the profile of stiffness matrix arising in finite elements problems. This method is suitable for cylindrical structures like electrical rotating machines and is especially intended for movement consideration by the moving band method. The structure is divided into sectors classified in a special way. The nodes contained in each sector are classified according to their radius value in regressing order. We show that the performances of the method are better than the most popular ones proposed in the literature. Application for a permanent magnet synchronous machine is presented. Application for finite elements analysis of a permanent synchronous machine in motion is achieved.

This paper presents the design of compact second-order bandpass filters based on dual-mode open-loop resonator. A filter design procedure is provided to facilitate the design process. The paper also describes the nature of the inherent transmission zero associated with the structure and presents a method of generating two additional zeros for improving stop-band performance. Finally, a filter design example is presented to validate the argument.

A printed loop antenna for integration into a compact, outdoor WLAN access point (AP) is presented. The loop design has a one-wavelength, resonant structure with respect to the center operating frequency of the 2.4 GHz band and is formed on a 1.6-mm thick FR4 substrate. The antenna substrate is further stacked above a system (PCB) of an outdoor AP by a small distance. In this study, the proposed design integrates the system printed circuit board PCB serving as an efficient reflector for the loop into an internal AP antenna solution. The results showed that by feeding the proposed square loop at one corner and adding the tuning portion at the diagonal corner, the dual-polarized radiation in the two major planes and good impedance matching over the band can be attained. High gain, directional radiation patterns were also obtained.

In this paper, a new method is proposed to calculate the simultaneous switching noise (SSN) in order to reduce the complexity of SSN circuit models and computational burden based on the rational function (RF) in time domain. The time-domain impedance function of a power delivery network (PDN) is calculated by approximating the impedance frequency response of a PDN with a rational function, and the SSN is calculated based on switching current characteristics. It is also found that the SSN can be suppressed through adjusting the period of time-domain impedance function and switching current. Compared with the results of lumped and distributed PDNs, the performance of the new method for calculating and suppressing the SSN is verified, and the simulation time of SSN is reduced effectively.