Recently, the number of electric vehicles (EVs) is increasing due to the declining of oil resources and rising of greenhouse gas emission. However, EVs have not received wide acceptance by consumers due to the limitations of the stored energy and charging problems in batteries. The dynamic or in motion charging solution becomes a suitable choice to solve the battery related issues. Many researchers and vehicle manufacturers are working to develop an efficient charging system for EVs which is based on magnetic emissions to transfer power. These emissions must be evaluated and compared to limits specified by standards (in and outside the vehicle) in order to not cause harmful effects on their environment (humans, pets, electronic devices...). This paper presents an efficient method for modeling electromagnetic emission in near field and sizing a magnetic shield for a wireless power transfer (WPT) system for EVs. A model based on elementary magnetic dipoles is developed in order to obtain the same radiation as the real WPT coil. This model is used to size a magnetic shield which will be placed under the vehicle to protect human body from magnetic emissions. The obtained shielding plate allows to respect the standards of magnetic emission by bringing a decrease of 43 dB to the levels of magnetic fields. This approach is experimentally validated.

A new local method for magnetic resonance electrical properties tomography (EPT), dubbed transverse-EPT (T-EPT), is introduced. This approach iteratively optimizes the dielectric properties (conductivity and permittivity) and the z-component of the electric field strength, exploiting the locally E-polarized field structure typically present in the midplane of a birdcage radiofrequency (RF) coil. In contrast to conventional Helmholtz-based EPT, T-EPT does not impose homogeneity assumptions on the object, and requires only first order differences, which makes the method more accurate near tissue boundaries and more noise robust. Additionally, in contrast to integral equation-based approaches, estimation of the incident fields is not required. The EPT approach is derived from Maxwell's equations and evaluated on simulated data of a realistic tuned RF coil model to demonstrate its potential.

This paper presents a free-space reflection measurement technique for estimating dielectric constant and loss tangent of different materials, demonstrated for rock samples, at S-band. The method is non-contact as well as non-invasive, which is used to characterize the electromagnetic properties of different materials (in our case, rock samples) at S-band in a non-anechoic chamber environment. The technique involves measurement of reflected signals (S₁₁ data from Vector Network Analyzer) from the material under test (MUT) as well as for the surroundings. By taking the inverse-Fourier Transform of S₁₁ data, the impulse-response corresponding to the reflected power from the MUT can be estimated. The proposed scheme overcomes the portability issue as well as the requirement of an anechoic environment. The measurement system consists of a single antenna (centered at 2.5 GHz), rock samples (i.e. material under test (MUT)), a perfectly conducting plate and a mounting fixture. By processing and analyzing the reflection coefficient data, the values of dielectric constant and loss tangent are calculated using the proposed algorithms which take care of clutter removal as well. The technique is validated using the estimated values of rock samples corresponding to their composition values available in the literature and found to be in good agreement. Estimation of dielectric properties of rock samples will be used to validate algorithms for science studies using SAR data of Chandrayaan-2 and other planetary missions. Hence, this measurement process will play a key role towards understanding of surface composition and features of the planetary bodies.

In this paper, a built-in hybrid magnetic bearing (BHMB) with a permanent magnet (PM) motor is proposed to reduce the axial length of the system. The BHMB shares the same distributed hollow rotor with an external PM motor. The structure and principle of BHMB are illustrated. The mathematic model of BHMB is deduced to design parameters, and the influences of parameters are analyzed. To improve the performance indexes of BHMB, a multi-objective optimization method based on Taguchi method is proposed. The values of parameters of BHMB can be chosen according to the proportion of each parameter. Finally, the finite element analysis (FEA) and experiment are used to verify the correctness of BHMB.

A dual-band wearable antenna operating at 2.45 GHz and 5.80 GHz with compact Artificial Magnetic Conductor (AMC) plane is proposed in this paper. The design is based on a U-shaped printed monopole antenna operating in the Industrial, Science, Medical (ISM) bands, and it is integrated with a square looped AMC plane which can reduce the overall size of the antenna system and realize miniaturization. The U-shaped monopole antenna is miniaturized by folding its arms, and its resonant frequency can be tuned easily by adjusting the length of two branches. The AMC unit, which is composed of concentric square double rings, realizes dual-band resonance. Meanwhile, a crossed patch is loaded into the inner ring to increase the electromagnetic coupling and reduce the resonance frequency of the two rings, thus miniaturizing the AMC unit. Therefore, the total size of the AMC plane which contains 3×3 elements is only 59.1 mm × 59.1 mm. Specific Absorption Rate (SAR) is examined by loading a three-layer human body tissue under the AMC antenna, and the simulation results show that SAR value is only 0.018 W/kg, which is far below the Institute of Electrical and Electronics Engineer (IEEE) standard. Finally, a prototype of the proposed antenna was fabricated and tested, and the experimental results agree well with the simulation responses.

A single-layer substrate integrated waveguide (SIW) longitudinal slot array antenna with low sidelobe level (SLL) in H plan and wide beamwidth in E plan is presented for 77 GHz millimeter-wave angular radar applications. The radiation energy of the antenna is determined by the length and offset of the slot. The conductance of the slot that satisfies the Taylor distribution can effectively suppress the sidelobe of antennas. Measured results indicate that the SLL of the E plane is -28.5 dB, and the 3 dB beamwidth is 98.3°. A measured peak gain of 12.7 dB is observed with a -10 dB impedance bandwidth of 75.5 GHz~77.4 GHz. The measured results are in good agreement with the theoretical calculations, and the proposed antenna has been demonstrated as a promising candidate used for millimeter-wave automotive angular radar for the proposed antenna array.

A sequence of anisotropic and isotropic materials of dielectric constant 12 and 10 respectively have been stacked alternatively to form a four-layer stack structure with aperture coupled feed mechanism for excitation. Applying this excitation, orthogonal mode pair TE_δ21^x and TE_2δ1^y has been excited at frequencies 7.54 GHz and 7.8 GHz, respectively in YZ and ZX planes to generate circular polarization. A circularly polarized bandwidth in the region (7.54 GHz-7.92 GHz) in conjunction with impedance bandwidth in the region (5.23 GHz-5.52 GHz) with a gain of 5.2 dBi has been accomplished. The designed antenna is appropriate for C-band and weather radar applications. The design assessment has been done using Ansys HFSS. The three stages of antenna design are examined. Further, the design is investigated with a 6-layer structure and an 8-layer structure.

In this paper, a triple-band reflective polarization converter with high efficiency for both linear-to-linear and linear-to-circular polarizations based on a metasurface is proposed, which can rotate a linearly polarized (LP) incident wave into its orthogonal direction with over 90% polarization conversion ratio (PCR) in the bands of 5.5-5.9 GHz (relative bandwidth of 7%) and 12-17.7 GHz (relative bandwidth of 38.4%). Besides, the proposed converter can also transform a linearly polarized incident wave to circularly polarized (CP) wave in the band of 6-12 GHz (relative bandwidth of 66.7%). Additionally, the performance of proposed polarization converter stays in considerable stability with the incident angle increasing 60˚ in circular polarization and 30˚ in linear polarization. Moreover, the physical mechanism of multiple resonances is discussed based on surface current distributions and equivalent circuit model. A prototype of the proposed converter is fabricated and measured, and the experiments and simulations are in great agreement. This polarization converter can be employed to manipulate the polarization of the signal in microwave communication.

The manuscript presents a log-periodic microstrip antenna with a defective ground structure (LPMADGS). The antenna is simulated, designed, and validated for C-band applications. The design of the antenna consists of three layers with upper most layer consisting of log-periodic, copper patches with a thickness of 0.035 mm; the middle layer is a 2 mm thick dielectric layer of FR-4 substrate; and the bottom layer is a defected ground structure (concentric ring resonators of 0.035 mm thickness). The suggested antenna design is simulated with a complete ground plane, without ground plane, and with a defective ground plane. The proposed antenna with optimized design is fabricated by wet etched method. The simulated results are approximately similar to the experimentally measured results. The experimentally measured results show transmission peaks at 7.65 GHz and 7.90 GHz. The resonating effect of log-periodic patches with a defected ground structure results in wide-band of 0.91 GHz (-10 dB bandwidth). The proposed antenna structure exhibits a wide bandwidth transmission which mostly resonates in frequency range that lies in C-band. It has future applications for mobile as well as wireless communication.

The goal of vector control of interior permanent magnet synchronous motor (IPMSM) is to make IPMSM have excellent dynamic and steady-state performance, but there is coupling between the d-q axis in the synchronous rotating coordinate system, which affects the torque response performance. In view of the fact that the traditional voltage compensation strategy is sensitive to the change of motor parameters, genetic algorithm is introduced to identify the parameters, and a feedforward voltage compensation control based on genetic algorithm parameter identification is proposed. The compensation voltage is calculated by the inductance and flux value of the motor identified by genetic algorithm. Compensation voltage is used to counteract the change of feedback voltage caused by the change of motor parameters in feedforward decoupling control. Simulated and experimental results show that the proposed strategy can effectively achieve d-q axis current decoupling, improve the dynamic performance of the system, and have excellent robustness.

This paper presents a multi-sections broad-band radio-frequency (RF) to direct-current (dc) power rectifier for pulsed signal transfer. The power transfer using a pulse allows to use a signal with low power spectral density. The optimal distributed configuration with critical parameters is studied to enhance the efficiency over broadband frequency and wide power range. A five stage distributed RF-dc converter arrangement with micro-strip transmission line ensures the power harvesting from 100 MHz to 11 GHz. The designed and fabricated circuit is characterized at multi-frequencies of ultra-wide band (UWB). The distributed harvester significantly improves the detected voltage over a wide bandwidth compared to conventional RF detectors. The achieved efficiency with optimized parameters is 48% with five-stage harvester. A maximum dc output of 956 mV is reached at 8 dBm of input power of sinusoidal single tone signal at 1 GHz of frequency. The designed prototype is associated with a square wave signal to show the circuit potential in terms of power transfer. The output voltage can be controlled with input signal level, frequency as well as the pulse width. For the power transfer circuit, 996 mV of maximum dc output voltage is reached for 1 V of input amplitude at 1 GHz with duty cycle of 50%. The efficiency increases significantly with duty cycle ratio of the input signal. The power harvester associated with a UWB antenna confirms the benefit of using a square wave signal in the case of power harvesting or transfer.

The deformation behaviors of a droplet on surface of composite insulator can strengthen local electric field, which could finally lead to flashover. Both experiments and numerical simulations for dynamic behaviors of a droplet on the surface of a composite insulator under applied AC voltage are investigated in this paper. Experiments are performed to study the influences of water droplet's volume and conductivity on the dynamic behaviors. Two critical parameters are proposed to describe the morphological change process of water droplet, and it is shown that the process can be divided into three stages. Moreover, these motion laws are explained by establishing theoretical factors and physical influence models. In addition, we perform computer simulation to study the dynamic behaviors of a water droplet under AC field, and the findings are in good consistency with our experimental results, proving the rationality of the theoretical physical model. It is found that the vibration frequency of droplet changes regularly with at different stages under the AC electric field.

A new method for obtaining an orthogonal system of eigenwaves of an open cylindrical waveguide filled with a gyrotropic medium and located in free space is presented. The advantage of the method is that it enables one to explicitly represent the fields of eigenwaves, which correspond to the discrete and continuous parts of the eigenvalue spectrum of such a guiding structure. Orthogonality relations for the eigenwaves and the procedure of expanding an electromagnetic field in terms of these modal solutions are discussed. The limiting transition from the case of a closed cylindrical waveguide with a perfectly conducting wall and a coaxial cylindrical gyrotropic core to the case of an open waveguide is considered. To illustrate the completeness of the obtained system of eigenwaves, a given field is expanded in terms of the found discrete- and continuous-spectrum waves and then resynthesized by evaluating the corresponding expansion numerically. Perfect coincidence between the initially specified field and the result yielded by this evaluation is demonstrated.

In order to solve the problem of the low direct control accuracy of permanent magnet assisted bearingless synchronous reluctance motor (PMa-BSynRM), which caused by transmission delay, the predictive control is applied to direct control of PMa-BSynRM. Meanwhile, in view of the disadvantages of large ripple (torque ripple, flux linkage ripple) and poor robustness in traditional predictive direct control (PDC), a fractional super twisting sliding mode controller (FSTMC) is proposed. Firstly, the mathematical models of torque and radial suspension force of PMa-BSynRM are derived. Secondly, the torque and flux controller based on FSTMC are designed, and the stability is verified. Thirdly, the torque predictive controller and levitation force predictive controller are designed, and the algorithm of PDC is described. Finally, the FSTMC-PDC system of PMa-BSynRM is built and simulated by Matlab/Simulink module. The simulated and experimental results confirm the validity and superiority of the proposed method.

A multiband hexagonal ring-shaped fractal antenna with stubs and slits loaded partial ground plane has been presented in this manuscript. The proposed antenna is compact in size 24×30×1.6 mm³ and exhibits enhanced bandwidth, gain, and reflection coefficient. Measured results exhibit that the proposed antenna resonates with impedance bandwidth (S₁₁ ≤ -10 dB) in the frequency ranges 1.0-2.75 GHz, 4.74-8.70 GHz, 11.04-12.76 GHz, 14.97-16.62 GHz, and 19.70-22.0 GHz. These frequency ranges cover distinct wireless standards such as 1800 MHz 2G spectrum of GSM band (1.71-1.88 GHz), LTE 2300/LTE 2500 (2.3-2.4 GHz/2.5-2.69 GHz), RFID/Bluetooth (2.4 GHz), 5G spectrum band (5900-6400 MHz) adopted by European Union, Long Term Evolution (LTE) band 46 (5150-5925 GHz), RFID (5.4 GHz), WLAN (5.15-5.35 and 5.72-5.85 GHz), Wi-MAX (5.25-5.85 GHz), FSS (11.45-11.7/12.5-12.75 GHz), defence systems (14.62-15.23 GHz), aeronautical radio navigations (15.43-17.3 GHz), and fixed/mobile satellite communications (19.7-20.1 GHz and 20.2- 21.2 GHz). The proposed antenna reveals the positive value of peak realized gain with almost omnidirectional radiation patterns in E- and H-planes for all the resonant frequency bands. The performance of proposed antenna has been realized by using HFSS V13 simulator based on FEM (Finite Element Method), and the results are compared with the experimental results which are in good agreement with each other.

An inset-fed planar MIMO antenna array design has been presented for dual-band 5G applications. The proposed MIMO array offers numerous advantages such as compact size, planar structure, and high isolation. The single element of the array comprises an inset-fed rectangular patch and open circuit stubs designed on the top side of the substrate, while the bottom layer consists of a partial ground plane. Simulated and measured results show that the proposed antenna offers dual-band characteristics at 28 GHz and 38 GHz frequency bands, respectively. It has also been observed from the results that the proposed inset-fed planar antenna offers good radiation characteristics, and acceptable gain and radiation efficiency. Furthermore, four-elements based MIMO antenna array has been designed for its possible use in 5G enabled communication devices. It has been demonstrated that the proposed MIMO antenna provides high isolation between array elements without disturbing the return loss of an individual element. The proposed MIMO antenna array has been fab- ricated and measured for the validation of simulation results, and it has been observed that both the results are in good agreement.

This paper shows a dual-band frequency and pattern reconfigurable antenna. The proposed antenna is designed on an FR4 substrate of thickness 1.6 mm and size 25×15 mm². Depending on the ON/OFF states of the PIN diode, the proposed antenna resonates at two distinct frequencies, i.e., 3.5 GHz, and 5.2 GHz, and has a pattern tilt from -170˚ to +160˚ in yz plane. In HFSS simulation, lumped RLC elements are used to reconfigure the antenna frequency and pattern. For switching, the PIN diode is used for frequency and pattern reconfiguration in the fabricated antenna to verify the simulated performance. In the simulated and measured performance, the proposed antenna shows reasonable matching. The proposed antenna is suitable for WiMAX and WLAN applications.

An inline quarter-mode substrate integrated waveguide (QMSIW) filter with controllable finite transmission zeros (FTZs) is presented based on a novel frequency-dependent coupling structure, which is constructed by a microstrip line with a pair of symmetric metallized via/buried holes and a magnetic coupling iris between two resonant cavities. FTZ can be independently introduced and controlled on both sides of passband to achieve high selectivity while keeping the filter compact configuration unchanged. For demonstration, the proposed structure is analyzed in detail. An inline fourth-order QMSIW bandpass filter (BPF) with two upper FTZs is designed, fabricated, and measured. The synthesis results, EM results, and measured results are in accordance with each other, which confirms the effectiveness of the proposed method.

The junction temperature change of SiC MOSFET will change its switching process, and then affect the electromagnetic interference (EMI) characteristics of the system where the device is located and the safe operation of the surrounding equipment. Therefore, it is of great significance to research the temperature dependence of its EMI characteristics. In this paper, a buck converter composed of SiC MOSFET is taken as the research object to study the temperature variation characteristics of the conducted EMI spectrum during the switching process. Combined with the specific circuit connection form of the buck converter, the coupling paths of the conducted EMI are determined, and then the influence mechanisms of temperature change on the differential mode (DM) interference and common mode (CM) interference are analyzed. The theoretical analysis and experimental results show that the DM interference of the buck converter composed of SiC MOSFET increases with the increase of temperature, and the CM interference is almost unaffected by temperature. When the working temperature increases from 25˚C to 145˚C, the peak value of DM voltage increases by 6.7 dBμV, and the peak value of CM voltage changes less than 1.4 dBμV.

The problem of direction of arrival (DOA) estimation based on a polarization sensitive array (PSA) is considered in this paper. In the environment of the mixture signal, a novel DOA estimation for both the independent signals and the coherent signals is proposed. The process of estimation is divided into two steps. First, the root-multiple signal classification algorithm is employed to estimate the DOAs of the independent signals. Then, the data covariance matrix which only contains the information of the coherent signals is estimated with improved vector reconstruction technique. Theoretical analysis and simulation results show that the proposed method can expand the array aperture and has small computation load as well as excellent estimation performance.