A multi-band antenna with omnidirectional radiation performance is proposed, which consists of 9 elements to form the structure of hexagonal prism. According to the placement rule, the antenna elements can be divided into two groups, one of which is placed in parallel on spaced three surfaces of the prism and the other placed vertically on the remaining spaced three faces of the prism. Each parallel element consists of two coplanar microstrip radiating patches which are nested within each other for miniaturization. Two parallel microstrips connected by a grounded disc with shorting pin are placed between the two patches to optimize the isolations. Each vertical element consists of two improved dipoles with four arms and a BALUN located at the back of the substrate plate which constitutes the quasi-Yagi structure. The resonant frequencies of the proposed prismatic antenna are 3.45 GHz, 4.9 GHz, 5.8 GHz and15.2 GHz which can be used for low frequency bands of the fifth generation (5G) wireless communications and wireless local area networks (WLAN) as well as satellite communication applications.

A compact 2×1 multiple input multiple output (MIMO) antenna system is designed to operate in the LTE band 40 (2.3-2.4) GHz. The proposed antenna consists of two circular patches fed using microstrip line. The antenna was initially designed to resonate at 5 GHz. Size reduction of 55.17% compared to conventional patch antenna is obtained after the inclusion of circular complementary split ring resonator (CSRR) in the ground plane. The resonating frequency was shifted to 2.34 GHz, there by the board size is compact (50×25×1.6 mm³). The designed antenna covers a bandwidth of 2.3 to 2.374 GHz with a maximum return loss of -27 dB at 2.34 GHz and isolation of -33.5 dB between the ports. The simulated correlation coefficient is approximately zero, and the total active reflection coefficient is 0.142 at the resonating frequency which are within the acceptable limits. The realized gain for the antenna is -8.9 dB.

Nine different strategies are proposed to compensate the cross-track motion errors in synthetic aperture radar (SAR) imaging, based on estimating the phase coefficients of the phase history. A spline interpolation method and a subaperture reconstuction method are used to derive the phase history over the whole aperture, based on the phase coefficients previously estimated. Four different scenarios are designed to compare the performance of these nine strategies.

The Conducted Electromagnetic Interference (CEI) characteristics in the primary circuit and at the ports of the secondary devices of the converter station of a UHVDC transmission system are researched comprehensively and systematically in this paper, by taking the Zhalute-Qingzhou ±800kV/10000MW UHVDC project in East Inner Mongolia of China as an example. The primary circuit equipment parameters of the target system are designed systematically at first, and the overall broadband equivalent model of the main circuit of the UHVDC system, which is composed of converter valve, converter transformer, filter banks and smoothing reactor, is developed. The CEI characteristics in the primary circuit under various conditions of the UHVDC system are analyzed based on the simulations carried out on the built BEC, and the influences of several primary circuit elements on the propagation of the CEI characteristics are researched. To improve the accuracy of the analysis of the CEI characteristics in the secondary device circuit, accurate BECs of the Capacitor Voltage Transformer (CVT), Current Transformer (CT) and secondary signal cable are established. The CEI characteristics at the ports of secondary devices under different operation modes are studied, and the influences of the cable length and burden rate on the CEI characteristics are analyzed. This paper provides a comprehensive and thorough understanding of the CEI characteristics of an UHVDC system.

A plasmonic induced transparency (PIT) structure is proposed and numerically investigated using the finite difference time domain (FDTD) method, which is achieved by the destructive interference between two graphene nano ribbon resonators and the bus waveguide. The common three-level atom system is used to explore the physical origin of the PIT behavior. The simulation results show that the PIT at different modes can be excited or suppressed by choosing the proper coupling position of the resonators. The peak and bandwidth of the transparent window are controlled by the coupling distance between the resonators and the bus waveguide, and the transparent window can be freely tuned by adjusting the chemical potential of graphene. The tunable PIT effect may offer a new avenue for novel integrated optical switching and slow-light devices in THz and mid-infrared frequencies.

In this paper, a three-layer circuit structure based on double-sided parallel-strip lines (DSPSLs) is proposed to design one out-of-phase power divider (PD) with equal power division and harmonic suppression. This PD, which is composed of four DSPSLs, one middle conductor, and two grounded resistors, features transmission suppression at two specified frequencies and all the even-order harmonics. Closed-form design equations are derived based on the traditional even- and odd-mode methods, and the circuit scattering parameters are also given. Finally, a practical PD operating at 0.92 GHz is designed and fabricated. The measured results show that this PD has equal power division with out of phase, harmonic suppression, good ports matching, and high outputs isolation.

A dual-broadband circularly polarized (CP) antenna with compact structure 97 × 97 × 0.8 mm³ is proposed. The measured -10 dB return loss bandwidth is 0.38 GHz (0.75-1.13 GHz) for UHF band and 0.81 GHz (2.32-3.13 GHz) for ISM 2.4 GHz band. The measured 3 dB axial ratio bandwidth is about 0.235 GHz (0.83-1.065 GHz) for UHF band and 0.34 GHz (2.36-2.7 GHz) for ISM band. The antenna consists of a feedline, patch, Stepped slot-1 and -2, a pair of orthogonal rectangular slots (H/V slot), and L-slot. There are two advantages for the proposed antenna: broadband and independent adjusting for UHF and ISM 2.4 GHz bands. The proposed antenna is a good candidate for worldwide RFID reader antenna.

A novel bearingless stirring permanent-magnet (PM) (BSPM) machine is proposed in this paper, which can offer high torque density, high efficiency, simple structure, and low cost. The novelty of the proposed machine is to provide a clean environment and no pinch-off areas in a stirred tank bioreactor and integrate appropriate magnetization directions of the PMs in the rotor. Firstly, the topology and operational principle of the proposed machine are described in detail. Then, the machine is designed for a given set of specifications, and its electromagnetic performances are analyzed by time-stepped transient finite-element method (FEM). Next, after the analysis of loss, a thermal simulation is established, complying with the design requirements. Finally, the efficiency and power factor map of the proposed BSPM machine are simulated for validation.

This paper presents the design of a flexible antenna using planar dipole with a reflector to achieve optimal radiation efficiency and low specific absorption rate (SAR) when the antenna is placed directly over the skin of body model. The antenna is designed for the 2.45 GHz frequency band. The parametric analysis of the proposed antenna is carried out. The proposed antenna achieves stable on-body performance: |S₁₁| varies from -16.05 dB (on skin) at 2.47 GHz resonant frequency to -16.40 dB (on skin) at 2.47 GHz resonant frequency to -16.40 dB (in free space) at 2.44 GHz resonant frequency. It was found that the maximum 1 g average SAR value is only 0.23 W/kg for an input power of 100 mW when the antenna is placed directly over the skin of a three-layer body model, and radiation efficiency is 20.5%. The measured results are presented to demonstrate the validity of the proposed antenna.

The effects of highly out-of-band electromagnetic interference (EMI) on an RF front-end are experimentally evaluated. Irradiation at 60 GHz with a moderate power is produced in the near-field owing to an open-ended WR15 waveguide fed by a Gunn diode. Surprisingly, we easily obtain the remote extinction of either the transmitter or the receiver of the front-end subject to EMI. The paper proposes a detailed analysis of both CW and chopped EMI by varying almost all experimental conditions, namely the polarization, target distance, and chopping mode. The latter shows most efficiency and evidences some long time scale dynamics in the induced perturbation.

Microwave staring correlated imaging (MSCI) achieves high resolution imaging results by employing the temporal-spatial independent radiation field. In MSCI, the imaging performance is determined by the independent degree of the radiation field. In this paper, a novel kind of ideal independent radiation field named the orthogonal radiation field (ORF) is constructed for MSCI. Firstly, a group of two-dimensional (2-D) orthogonal basis functions are used to construct the ideal ORF samples. Then a method is proposed to construct the ORF samples by designing the transmitting signals. The numerical simulations validate the feasibility of this method. Finally, when the ORF is applied in MSCI, the numerical simulations achieve high resolution imaging results and demonstrate good imaging performance that is robust to noise.

An adaptive sharp boundary inversion scheme is developed to improve resolution with feasibility for transient electromagnetic (TEM) data inversion. By using weighted minimum gradient support (WMGS) constraint, this method focuses the resistivity change areas on layer boundary locations. Prior information describing roughness can be added into the constraint to improve resolution. Furthermore, even though no prior information about layer boundaries is available, it can still reconstruct models with geo-electrical interfaces. Synthetic models prove that this method has a better performance in presenting layer boundaries than smooth-model inversion. Field data of a TEM test line are inverted using this method, which makes the basement layer visualized easily.

A new architecture for a low profile miniaturized frequency selective surface based on complementary structure capable of providing a high angular stable performance is proposed. The proposed FSS is composed of an array of convoluted cross dipoles and its complementary slots pattern that is separated by a thin dielectric substrate. An equivalent circuit model for this FSS is presented to provide a deep insight into the mechanism of reducing the unit size by shifting and lengthening the dipoles. With the use of this method, the FSS unit cell size has been significantly reduced to only 0.0085λ×0.0085λ, and the thickness is 0.000093λ, where λ represents the resonant wavelength in free space. Moreover, the proposed FSS achieves good stability in the scope of incidence angles of 86 degrees for both TE and TM polarizations. Besides, the length of the dipoles can tune the resonant frequency.

In this paper, we study the design and homogenization of bianisotropic metamaterials originated from planar split-ring resonators, which would potentially meets the requirements of the emerging photonic topological insulators and some other types of extotic photonic materials with non-trivial states. We show that the off-diagonal elements in the magneto-electric tensor can be realized by combining the planar split-ring resonators with different orientations. To ease the fabrication process, a layer-bylayer design of metamaterials with desired bianisotropy is proposed. The design and homogenization procedure of such metamaterials are verified through effective parameter retrieval approach and computer based simulation. With the proposed structure, the complex magneto-electric coupling is realized in layered structures through planar techniques, which may be useful in the terahertz and optical range.

This paper describes an analytical subdomain model to predict the magnetic field distributions in the semi-closed surface-mounted permanent magnet synchronous machines (PMSMs) due to magnet segmentations with radial magnetization (RM). The magnet segments per pole can be virtually represented by finite number of permanent magnet (PM) blocks and Fourier decompositions. The model can also determine the optimum magnet pole-arcs for each segment and the optimum airgap spacing between the segments. The analytical model is then applied to evaluate the performance of a three-phase, 12-slot/8-pole, surface-mounted PMSM having two segmented magnets per pole with RM. With design objective for minimum cogging torque and minimum total harmonic distortion in phase back-emf waveforms, we obtain that the optimum settings are 147.6° elect. for magnet segment pole-arc and 11.2° elect. for airgap spacing between the magnet segments. These analytical results are further compared and validated by 2-D finite element analysis (FEA). Additionally, we also compare the results with those from the optimum magnet pole-arc of one magnet segment per pole machine. It is observed that the cogging torque and total harmonic distortion THDv of the phase back-EMF are significantly reduced by 89% and 25%, respectively, with constraint and assumption that both machines utilize similar total magnet volume.

We propose a generalized hybrid method to achieve time efficient and accurate solutions for electromagnetic scattering and radiation problems involving complex scenes with multiple objects. The method utilizes frequency domain solutions, and is based on dividing the original computational domain into smaller sub-domains. Each sub-domain is first solved independently, then the interactions between the sub-domains are accounted for through an iterative procedure. The main difference of the proposed hybrid method in comparison with the current hybrid methods or the domain decomposition methods available in the literature is that the proposed method allows users to have the freedom to choose from a variety of techniques for each sub-domain; such as integral equation (IE), analytical and asymptotic methods that suit the problem at hand best. Current hybrid or domain decompositions methods rely on a predetermined combination of numerical techniques. This flexibility in the choice of the method employed for each sub-domain in the generalized hybrid method is achieved by creating an interface capable of interacting between the different sub-domains properly. Furthermore, the method renders to parallel implementation as each sub-domain is solved independently. The hybrid method in its current state can be applied to two different scenarios: (i) multiple non-touching homogeneous objects, and (ii) inhomogeneous objects. Numerical examples of various combinations of IE, analytical and asymptotic methods are presented to validate the accuracy and the robustness of the generalized hybrid method.

This paper presents a design of multi-band array antenna based on Double Negative Metamaterial (DNM) unit cells for multi-automotive applications. The antenna consists of 4×4 rectangular and circular radiating patches connected in series using microstrip lines and fed by a 50 Ω corporate microstrip line. An array of 4×6 wire loaded complementary spiral resonator (CSR) unit cells is placed on its reverse side to provide miniaturization and multiband features to the proposed design. The reflection coefficient (S₁₁), mutual coupling, effective diversity gain (EDG), envelope correlation coefficient (ECC), and radiation patterns are evaluated for four elements of the proposed antenna placed in four different locations on the car body model. Simulations and measurements indicated that the proposed antenna features a low mutual coupling (<-34 dB), low ECC (<0.0001), high EDG (>9.99), high efficiency (72%-95%), and low on-car detuning over the operating frequency bands. The proposed antenna covers five bands; 1.99 GHz to 3.03 GHz, 5.15 GHz to 6.369 GHz, 7.67 GHz to 7.99 GHz, 9.91 GHz to 10.23 GHz, and 11.79 GHz to 12.2 GHz. The performance of ECC between four antennas on car body has been investigated in different cases of isotropic, indoor, and outdoor. The metallic effect on antennas performance also has been investigated by evaluating the mutual coupling and transmission coefficient between two antennas served as transmitter and receiver with presence of car body. The results show transmission coefficient of proposed DNM antenna with metallic presence almost identical to free space across desired frequency bands. With all capabilities mentioned the antenna has potential for WiFi/WiMAX, Vehicle-to-Vehicle (V2V), transportable earth exploration satellite, military requirement for land vehicles, and earth stations on vessels applications.

Iron-nickel nanotubes consisting of 20% of Ni and 80% of Fe with an aspect ratio of about 100 were synthesized by electrochemical deposition in the pores of the polyethylene terephthalate ion-track membranes. The main morphological parameters such as composition, wall thickness and structural characteristics were defined. Macro- and micromagnetic parameters of FeNi nanotubes were determined.

A novel low-index metamaterial lens (LIML) used for wideband circular polarization antenna is proposed. By introducing gradual spaces between metamaterial elements, one can achieve a much wider bandwidth than the equally spaced situation can do. Starting with a planar equiangular spiral antenna with reflector, we demonstrate the design idea of this LIML. By using the specially designed LIML, the ultimate antenna can achieve an obvious gain improvement of 2 dBi and a wide axial ratio bandwidth of 44% (from 6.9 GHz to 10.8 GHz). A prototype is fabricated, and the measured results agree well with the simulated ones.

A new method for calculating the time-domain (TD) transfer function of ultra-wide band (UWB) antennas, which is used for measuring the electromagnetic pulse (EMP) at VHF, is proposed. The phase of the complex antenna factor is constructed based on the Hilbert transform that describes the relationship between the phase and amplitude of a signal in frequency domain (FD). The detailed steps for calibrating the TD transfer function are discussed, and the calibration uncertainty, whose maximum value equals 2.79 dB, is estimated. The presented method is verified by TEM cell calibration, in which the TD transfer function of a wideband antenna is calculated and used to reconstruct time domain electromagnetic pulse. The results show that the difference between the calibrated result with TEM cell calibration and the reconstructed result is 0.58 dB.