At present, Feature Selective Validation(FSV) is the most common data verification method of computational electromagnetics, and its effectiveness has been verified since its release in 2006, but since the main research object of this method is electromagnetic compatibility data, the 8 sets of data used for algorithm training also come from the field of electromagnetic compatibility, and its data curve has the characteristics of gentle waveform and small fluctuations. However, Radar Cross Section(RCS) data, especially high-frequency RCS data, usually have complex waveforms and drastic fluctuations, and the results obtained by the FSV method are often quite different from those obtained by experts. This paper proposes a new data verification method based on Smoothed Pseudo Wigner-Ville Distribution(SPWVD) algorithm for RCS data, which integrates the characteristics of RCS data and expert evaluation experience, and verifies its effectiveness in RCS data verification.

Spoof surface plasmon polariton (SSPP) transmission lines (TLs) provide a possible way to confining transmitted signals in deep subwavelength scale. SSPP TLs can suppress the mutual coupling between adjacent channels and improve the signal integrity, providing a promising alternative to conventional transmission lines. However, SSPP structures generally possess strong chromatic dispersion (i.e. signals at different frequencies propagate with different velocities), resulting in significant pulse distortion. Such drawback greatly hampers the practical application of SSPP TLs, especially in the long range transmission. To tackle this bottleneck problem, we propose a dispersion-compensation mechanism, where a section of judiciously designed TL with an opposite-dispersion characteristic is added to the SSPP circuit to achieve minimized total dispersion of the link within a broad frequency range. The experimental results indicate an impressive improvement of 72.46% for the SSPP transmission line in the stability of the circuit group delay after applying the dispersion compensation approach. This hybrid transmission line has high transmission efficiency without inducing group delay dispersion of the signals. Our design scheme can be easily extended to other frequency band, offering a possible solution to high-performance signal transmission in future integrated circuits.

We present an advanced approach to wave manipulation utilizing mmWave wide bandwidth, enhanced gain, and extensive spatial coverage through a 1-bit stacked patch reconfigurable intelligent surface (RIS). The RIS was designed on a four-layer board based on RO4350B, featuring a stacked patch on the front and phase-shifter components with a biasing line on the back of board. This sophisticated RIS comprises 400 elements, with a total array size of 100 × 100 mm², providing a remarkable bandwidth of 7.02 GHz to cover the n257 band. Through a meticulous blend of simulations and real-world implementation, we emphasize the adaptability of the RIS in steering beams, maintaining a minimum gain variation and ensuring the gain of 21.03 to 15.17 dBi up to ±80˚ beam steering on normal incidence. Our study explores various beam manipulation scenarios, including near-to-far-field, far-to-far-field, and far-to-near-field transformations. The successful fabrication of the proposed RIS, combined with communication performance tests across the n257 band, underscores the practical applicability and robust performance of the system in real-world scenarios, thereby ensuring link throughput. The comprehensive investigation provides valuable insights into the design, simulation, fabrication, and performance evaluation of mmWave RIS. The successful integration of theoretical insights with empirical validations positions the present study at the forefront of mmWave innovation, with significant implications for the future of various research and wireless communication technologies.

This paper introduces the configuration of a microstrip antenna array with a new Archimedean spiral sequential feed network (SSFN) for the upper half of the C-band application. The Archimedean SSFN mechanism uses four circular patch elements to structure the proposed antenna array. The optimized reflection loss (S₁₁) of the proposed SSFN mechanism was obtained by tuning the dimensions of each transformer and then connected with an antenna array. Aiming to make the suggested antenna array compact in size, bending feed lines were utilized. The antenna array is designed with overall physical dimensions of 75 mm × 75 mm × 1.575 mm, with an electrical size of 1.85λ_o mm, 1.85λ_o mm, 0.038λ_o at a frequency of 7.43 GHz. An equivalent circuit model (ECM) is designed and analyzed to verify the proposed Archimedean SSFN and the designed antenna array. Reflection losses of SSFN and microstrip spiral antenna array (SAA) were confirmed with the suggested circuit model utilizing Computer Simulation Technology (CST) Microwave Studio and Applied Wave Research (AWR) Microwave Office software. According to the empirical results, the SAA has a reflection loss bandwidth of 2.08 GHz (6.15-8.23 GHz) and a maximum gain of 10.2 dBi at 7.43 GHz. The axial ratio (AR) of the proposed antenna covers a bandwidth of 1.6 GHz (6.2-7.8 GHz), which is approximately 22.85% of the entire bandwidth. These results demonstrate a perfect agreement between the simulated and measured outcomes, making the suggested SAA suitable for the C-band wireless application.

In this paper, a systematic and efficient method is proposed to collectively synthesize the pattern for multiple antennas on high-speed railways (HSRs) based on pixel structures and N-port network, achieving an overall omnidirectional circularly polarized (OCP) pattern over a broad elevation angle. The integration of flush-mounted antennas not only enhances communication quality but also eliminates the undesired aerodynamic drag. Network parameters and radiating features of the N-port network based on the pixel structures are firstly retained through full-wave simulations. Subsequently, without resorting to extra simulations, the configurations of multiple antennas are precisely synthesized through numerical calculations. The beam direction and beam width of each element can be automatically adjusted, promoting a seamless omnidirectional radiation feature. Following the approach, the proposed antenna thoroughly cover the 5G N41 band (2.515-2.675 GHz), delivering omnidirectional, high-gain, right-hand CP radiation throughout the entire 160 MHz band from θ = 50˚ to 100˚. The averaged CP gains and ARs reach 6.09 dBi and 2.36 dB, respectively, within the target region. The antenna system was validated experimentally, with the measured results agreeing well with the simulated ones. Such radiating characteristics perfectly match the established base stations antennas.

With the advancement of the intelligent process, all kinds of electrical equipment are highly dense in space, and the impact of electromagnetic interference on high-precision electronic equipment cannot be ignored. Metal shielding shell is one of the effective means to reduce electromagnetic interference. The heat dissipation holes on the surface of the shielded box are often used to maintain the normal operating temperature of the internal equipment, which will reduce the electromagnetic shielding effectiveness of the box. At the same time, due to the existence of capillary effect, condensation is very easy to occur at the hole gap, and the corrosion caused by it will further reduce the overall shielding effectiveness of the metal box. At present, there are few studies on the integrated prediction of ``condensation-corrosion-shielding effectiveness'' of metal boxes. Based on the commercial multi-physics simulation software COMSOL, this paper first simulates the condensation of a metal box in a high-humidity environment by constructing temperature, humidity, and moisture transport fields. Then, the current field and deformation field are constructed to predict the corrosion phenomenon at the gap of the metal box, and finally the electromagnetic field is constructed to predict the electromagnetic shielding efficiency of metal boxes at different frequencies. The joint multi-physics coupling simulation of condensation, corrosion and electromagnetic shielding effectiveness phenomena is realized.

In this paper, a unique low profile double stubbed ground plane frequency reconfigurable circular monopole antenna is introduced. The ground plane contains two RF-PIN diodes that enable the antenna to be reconfigured in ultra-wideband (3.2-10.8 GHz) and dual frequency (2.8-4.01 GHz and 7.56-8.2 GHz) modes. The proposed antenna is designed using an FR-4 substrate with the dimension about 33 × 28 × 1.6 mm³. The impedance matching of the antenna at ultra-wideband operation is improved by a defected ground structure. The measured and simulated results of the antenna are in close agreement. This antenna is useful for cognitive radio application.

A compact dual-element microstrip antenna, employing a parasitic artificial magnetic conductor (AMC), is proposed for facilitating 4G and 5G wireless communications. The antenna design entails microstrip dipoles fed by a T-shaped feedline. Notably, the antenna achieves a measured bandwidth of 5.35-6.7 GHz (with S₁₁ ≤ -10 dB). To enhance performance, a proposed parasitic AMC reflector is integrated into the antenna structure. Incorporating a 3 × 3 AMC array, the antenna extends its -10 dB measured bandwidth from 4.57 to 6.80 GHz, catering to both 4G and 5G communication standards. Comparative analysis with an antenna lacking AMC reveals a reduced size of 34%, alongside a notable gain of 8 dBi and unidirectional radiation patterns. Additionally, a low-profile wideband two-element array, coupled with a 3 × 4 AMC reflector, demonstrates a broad bandwidth spanning from 4.55 to 6.8 GHz within the C-band. This configuration results in increased gains for the two antenna elements and ensures acceptable isolation exceeding 30 dB, crucial for multiple-input multiple-output (MIMO) systems. The efficiency and gain of all elements are obtained almost 90% and 8 dBi, respectively. Moreover, an AMC unit cell, well founded on a parasitic patch, resonates at 6.12 GHz with a bandwidth extending from 5.25 to 7.15 GHz. Furthermore, the offered equivalent transmission line model of the antenna with the AMC is demonstrated, yielding desirable results. This model accurately predicts the input impedance of the 1 × 2 array with AMC across a broad frequency band ranging from 4.63 to 6.73 GHz. This comprehensive coverage demonstrates the effectiveness and versatility of the offered model in characterizing the electrical behavior of the antenna system across a wide frequency band, thus facilitating its design and optimization for various applications.

A novel miniaturized lens unit at 2.45 GHz is presented in this manuscript. This unit is formed by a modified Malta cross and an ordinary cross, with a unit period of 0.2λ₀, where λ₀ denotes the unit wavelength. The ordinary cross unit creates a pathway for current between two units. Accordingly, it increases the current path and reduces the unit volume to a quarter of its original size. By adjusting the length of the Malta cross arm, it is possible to achieve the transmission phase at 2.45 GHz within a range of 0-360˚. Moreover, an improved PSO algorithm is used to optimize the phase of array elements. The optimization process is able to achieve a phase-shifting of ±18˚ within the range of 3.28λ₀. Simulation and measurement results show that the miniaturized lens unit can be used in the wireless energy transmission system.

This paper presents a dual band orthogonal quad-element multiple input multiple output (MIMO) antenna for C-band and X-band applications. Each antenna element of the proposed MIMO antenna contains a deformed rectangle-shaped radiating patch etched with two circular slots of different radii on the top surface and partial ground plane in the bottom surface. The modified partial ground structure is used in the bottom to enhance the bandwidth of the antenna. The orthogonal arrangement of the proposed quad-element MIMO antenna is designed and fabricated with a distinct gap of d>λ/2 between individual antenna elements. The interconnected ground plane was introduced in the bottom of the proposed quad-element MIMO antenna for high isolation. The proposed MIMO antenna has an overall size of 1.69λ × 1.69λ × 0.022λ (at 4.23 GHz) and exhibits the measured double operating bands (S₁₁<-10) covering 4.23-4.55 GHz and 6.30-10.22 GHz with high isolation of >27 dB and >32 dB respectively. Both the operating bands have simulated peak gain of 5.73 dBi and peak efficiency of 72% over the entire operating range. Furthermore, the presented antenna has good diversity performance with envelope correlation coefficient (ECC) < 0.001, diversity gain (DG) of 9.996 dB, and total active reflection coefficient (TARC) < -10 dB. The simulated and measured results of proposed MIMO antenna are in good agreement.

Modern small satellite development represents a new trend, a new design idea, and it can be used as a transmitter to assist helicopter monitoring. The imaging model of the arc array bistatic SAR with a small satellite transmitter is studied. Due to the long resident time of small satellite platform and the wide-area observation capability of arc antenna, it has a wide application prospect in the field of earth detection and remote sensing. However, the motion state of the small satellite and the special scanning mode of the arc antenna have some effects on the SAR imaging results. Therefore, the imaging geometry of the arc array bistatic SAR with a small satellite transmitter is established, and an improved Chirp Scaling imaging algorithm is proposed. Firstly, the motion compensation function is used to compensate the migration caused by the high-speed motion of the small satellite. Then, the two-dimensional spectrum is derived by using standing phase principle and scaling function. Next, the coupling between range and azimuth is compensated by consistent range migration correction and secondary range compression, and residual phase is compensated in azimuth frequency domain. Finally, simulation results verify the effectiveness of the proposed method.

A novel three-unit 8/4 wide-rotor bearingless switched reluctance motor has been designed to address the challenges of strong coupling and control difficulties between torque and suspension force in traditional bearingless switched reluctance motors. This motor features independent torque flux paths and suspension flux paths, allowing for separate control of torque and suspension force similar to traditional switched reluctance motors and active magnetic bearings. To tackle issues such as torque ripple, suspension force ripple, and reduced system robustness caused by external disturbances during operation, a torque sharing function and a suspension current PWM control strategy based on active disturbance rejection technology have been proposed. Firstly, mathematical models for the torque and suspension force of the three-unit 8/4 wide-rotor bearingless switched reluctance motor were established using Ansys simulation data and the Maxwell stress method. Subsequently, a torque sharing function and a suspension current PWM control system were developed based on these mathematical models. The endpoint of the commutation overlap zone was set at the maximum value of the phase inductance to eliminate the weak coupling effect of torque current on suspension force. Finally, active disturbance rejection control technology was introduced to compare its performance with that of traditional PID controllers in suppressing interference. Simulation results demonstrate that the proposed method ensures decoupling switching between each phase's motor torque and its associated suspension while enhancing anti-interference performance.

Chirality (mirror asymmetry) of the unit cell ensures the phenomenon of polarization conversion in a metamaterial/metasurface. In this communication, we control the polarization conversion and asymmetric transmission properties of a metasurface by controlling the chirality of its unit cells. Radio Frequency PIN diode switches are used to control the chirality. When the switches are turned OFF, the unit cells become chiral, and the metasurface successfully exhibits polarization conversion as well as asymmetric transmission for linearly polarized incident waves. When the switches are turned ON, the unit cells become achiral and lose both the above properties. The polarization conversion switching phenomenon is also observed for circularly polarized incident waves. A simple ultrathin metasurface is designed and fabricated to demonstrate these properties.

A broadband circularly polarized (CP) antenna with both a wide half-power beamwidth (HPBW) and a wide axial ratio beamwidth (ARBW) is proposed. The proposed antenna is composed of a pair of crossed dipoles and a U-shaped metal reflecting cavity. The fan-shaped patches of the dipoles can effectively increase the operating bandwidth of cross dipoles, and the U-shaped metal reflecting cavity can further increase the impedance bandwidth (IBW) and axial ratio (AR) bandwidth of the antenna while enhancing HPBW and ARBW. To validate the feasibility of the design, the proposed antenna is fabricated and measured. The measured results show that the bandwidths of the antenna are 89.2% for -10 dB impedance and 82.7% for 3 dB AR. In addition, both HPBW and ARBW greater than 120˚ are achieved within a relative bandwidth of 63.1%.

Fault Tolerant Permanent Magnet Vernier Rim-Driven Machines (FTPMV-RDM) have attracted much attention due to the advantages of high torque density and good fault tolerant capability. However, the traditional FTPMV-RDMs have a lower power factor which limits their broad application in marine electric propulsion system. This paper proposes a high power factor FTPMV-RDM topology in which the flux-concentrating Halbach array magnets are mounted on a rotor, and isolation slots are arranged on the stator teeth. A preliminary design of the FTPMV-RDM is presented. To tackle the problems of large computational burden and poor accuracy in traditional multi-objective genetic optimization algorithms, a novel optimization design method combining sensitivity-based optimization with sensitivity analysis is proposed. The performance of the machine is analyzed using Finite Element Analysis (FEA), and the results show that the proposed machine topology features a high power factor, high torque density, and strong fault-tolerant capability.

In this paper, a miniaturized 4-port (4 × 4) multiple-input multiple-output (MIMO) antenna is presented in the Ku band with operating frequency range of 16.9 GHz to 17.9 GHz. The presented antenna incorporates Substrate Integrated Waveguide (SIW) Technology with each element of MIMO in Quarter Mode Substrate Integrated Waveguide (QMSIW). The radiating features of the antenna are incorporated by inserting periodic slots in the patches as well as defective ground plane (DGS) technology in lower ground. For achieving good impedance matching and isolation, DGS and SIW technologies are incorporated in the design. An isolation greater than 30 dB is achieved in the complete operating range (16.9 GHz-17.9 GHz). The MIMO antenna is realized physically in Rogers 5880 with dimensions of 36 × 36 mm². The MIMO antenna properties like Envelope Correlation Coefficient (ECC), Channel Capacity Loss (CCL), Total Effective Reflection Coefficient (TARC), Mean Effective Gain (MEG) and Diversity Gain (DG) are analysed to validate good agreement with the standard values.

Space vector pulse width modulation (SVPWM) is widely used in three-phase inverters. As the performance requirements of inverters increase, there is a demand to suppress common-mode voltages (CMVs) generated by SVPWM. In order to suppress the CMVs, it is necessary to mathematically analyze the CMVs. By using a mathematical analysis method based on double Fourier series, general expressions of CMV harmonic amplitudes and spectra are obtained for seven-segment SVPWM and five-segment SVPWM. Comparative analyses on the CMV general expressions are performed for the two SVPWMs, and the CMV harmonics characteristics for the two SVPWMs are summarized. Simulations are carried out in an inverter-driven permanent magnet motor system, and simulation results are in good agreement with calculation ones, which verifies the correctness and validity of the mathematical analysis. Based on these analyses, a more in-depth research can be conducted on the CMV suppression.

This paper presents a compact 8 × 8 multiple-input-multiple-output (MIMO) antenna system designed to operate across two wide frequency bands suitable for fifth-generation (5G) mobile network and wireless local area network (WLAN) applications. Each antenna element comprises a radiator, a feeding line, and a defected ground plane. Each radiator consists of a first L-shaped radiator (FLR), a second L-shaped radiator (SLR), and an extra radiator (ER). To enhance the isolation, a defected ground structure (DGS) is employed between the antenna elements. The presented antenna operates across three frequency bands, namely, 3.5 GHz (3.3 GHz-3.8 GHz) and 4.9 GHz (4.8 GHz-5 GHz) 5G frequency bands, and 5.7 GHz (5.15 GHz-5.85 GHz) WLAN frequency band, exhibiting excellent isolation, surpassing 15 dB in both lower and higher frequency bands. The overall efficiency exceeds 58%, with an envelope correlation coefficient (ECC) value below 0.125.The simulation and measurement results are in good agreement.

Weight and reference signal are utilized in adaptive interference cancellation (AIC) for vector weighting to generate the signal with equal amplitude and opposite phase to the interference signal. Weight accuracy becomes the core factor to determine the performance of the AIC. In this letter, we analyze the influence of the weight accuracy on interference suppression performance, propose the quantitative characterization method of the weight accuracy with weight noise as an indicator, study the performance and influencing factors of the weight accuracy, and propose the optimization design method. The characteristics of weight accuracy in interference cancellation are verified by theoretical simulation analysis. This work fills in the blank of weight accuracy analysis and has solid theoretical value for exploring the capability boundary of the AIC.

The Method of Moments (MoM) is a non-embedded uncertainty analysis method that has been widely used in Electromagnetic Compatibility (EMC) simulations in recent years due to its two major advantages of high computational efficiency and immunity from dimensional disaster. A random variable sensitivity calculation method based on the Complex Number Method of Moments (CN-MoM) is proposed in this paper to improve the accuracy of the MoM in standard deviation prediction and thereby enhance the credibility of EMC simulation uncertainty analysis results. In the parallel cable crosstalk prediction example in the literature, the result of the Monte Carlo Method (MCM) is used as the standard, and the accuracy of the new method proposed in this paper is quantitatively verified using the Feature Selective Validation (FSV) method. Compared with the MoM, the proposed method can significantly improve the calculation accuracy of the standard deviation results without sacrificing simulation efficiency.