A novel high-selectivity bandpass filter based on a defected ground structure and substrate integrated coaxial line is proposed. Three transmission zeros near the passband are achieved by introducing a divergent-shaped resonator and two spindle-shaped defected ground structures, resulting in a high selectivity. To verify the proposed structure, one prototype with a center frequency of 4.94 GHz is designed and fabricated. The measured results show that three transmission zeros respectively located at 3.92, 4.36, and 6.00 GHz are obtained. The 3-dB passband bandwidth is 14.2% from 4.59 to 5.29 GHz. The upper stopband rejection is better than 20 dB from 5.71 to 11.31 GHz.

A triple band artificial magnetic conductor (AMC) featuring zero reflection phase at 1.18 GHz, 1.59 GHz, and 2.45 GHz is designed and modeled. A square patch is used to achieve the first resonance. The other two resonance frequencies are generated by two square slots inserted in the first patch. All the three resonant frequencies are adjusted independently of each other and easily predicted by the developed analytical model. A good agreement between electromagnetic simulation and analytical results is obtained with a resonance frequency shift lower than 120 MHz.

The trajectory of the polarization state of a monochromatic beam passing through a fixed linear polarizer and a rotating elliptical retarder on the Poincaré sphere is found to be a three-dimensional 8-shaped contour, which is determined as the line of intersection of a right-circular cylinder with the Poincaré sphere. The cylinder is parallel to the S3 axis, and the projection of the contour on the S₁S₂ plane is a circle whose center and radius are determined. A method of projecting the three-dimensional geometric relationships to the two-dimensional S₁S₂ plane to locate the position of the polarization state of the emerging beam on the Poincaré sphere for a given azimuth of the elliptical retarder is presented, and applied to solve a problem of polarization optics. The proposed graphic method substantially simplifies the polarization state analysis involving elliptical retarders.

Bessel beam is an important propagation-invariant optical field. The size and shape of its central spot remain unchanged in the long-distance transmission process, which has a wide application prospect. In this paper, we find that zero-index media (ZIM) metalen can be designed to realize the unique Bessel beam. On the one hand, based on the metal-dielectric multilayered structure with sub-wavelength unit cells, the anisotropic epsilon-near-zero media (ENZ) metalen is proposed for generating the robust Bessel beam, which is immune to the defects placed in the transmission path or the inside of the structure. The ZIM metalens uncover that ENZ media provide a new way to generate Bessel beams beyond the conventional convex prisms. On the other hand, with the help of the uniform field distribution of ZIM, enhanced (multi-channel) Bessel beams based on multiple point sources (exit surfaces) are studied in the isotropic ENZ metalens. In addition, the Bessel beam generated by the ZIM metalen has also been extend to the epsilon-mu-near zero metamaterial realized by two dimensional photonic crystals. Our results not only provide a new way to generate Bessel beam based on the ZIM metalens, but also may enable their use in some optical applications, such as in fluorescence microscopy imaging, particle trapping, and wave-front tailoring.

A miniaturized half-mode substrate-integrated-waveguide (HMSIW) based bandpass filter with defected ground surface (DGS) for sub-5G applications is presented in this research. The novelty in this article is the proposal of an original configuration of an SIW Filter composed of a mix of DGS cells; each couple of C shapes is etched exactly beneath of two cross shapes, which give us long rejection. We have used six periodic cross-shaped slots as DGS in top of the cavity plane for disturbing the current and creating stopband rejection, and we have also used three couples of C-shaped DGS cells in the bottom plane to improve the performances of the proposed filter. This novel bandpass filter is developed on a 1.54 mm-thick FR-4 (with relative permittivity of 4.3 and the tangent loss of 0.025) operating in the band ranging from 3.4 GHz to 3.8 GHz with a bandwidth of 400 MHz and having the size of 13.5 × 38.6 mm². The proposed HMSIW-based filter is simulated, fabricated, and measured. The measurement results are in decent agreement with the simulation results.

In order to reduce the electromagnetic interference on the receiving side of electronic equipment in the process of wireless energy supply, a magnetic coupling resonant wireless energy supply system for portable electronic equipment with double-layer PCB coil structure is designed under the condition of 100 kHz. Firstly, the circuit principle is analyzed, and the compensation circuit model of LCC-P is established; Then, the coil model is constructed and optimized, the effects of turns and wire diameter on the coil self inductance and coupling coefficient are analyzed. The best parameters are selected, and the magnetic field distributions of the three coil structures at different distances are simulated and studied. Finally, an experimental platform is built to study the transmission efficiencies of different receiving coils at different spacings. The magnetic field intensities at different positions are compared to further verify the performance of double-layer coils. The experimental results show that when the coil spacing is in the range of 4-16 mm, the efficiency can reach 40%-71%. The central magnetic field of the coil is increased by 16%, and the external magnetic field is reduced by more than 20%. The temperature rise of one hour charging is 5.34˚C, which is only 0.78˚C higher than that of other coils

Multi-carrier Phase Coded (MCPC) signal has the advantages of large time-bandwidth product, low intercept, anti-jamming, digitization, flexible waveform, and high spectral utilization, and has become a hotspot in radar waveform research. However, MCPC signal has high-distance sidelobes which are difficult to suppress, after pulse compression processing. Excessive sidelobes will mask the existence of small and weak targets, thus losing the target signal, which limits the practical application of MCPC signals. Therefore, it is of great significance and practical value to study the sidelobe suppression of MCPC signals. From the point of view of waveform design, a multi-carrier phase-encoded signal combining chaotic encoding and single encoding (MCPC-CS) is designed by using chaotic sequence as phase encoding of MCPC signal and optimizing it. In this paper, peak sidelobe level ratio (PSLR) is used as a evaluation factor of the autocorrelation function. The simulation results show that MCPC-CS signal has a good autocorrelation peak sidelobe level ratio, and the autocorrelation sidelobe is reduced by more than 3 dB compared with the normal MCPC signal.

In order to solve the nonlinear couplings among speed and the radial displacement of the outer rotor coreless bearingless permanent magnet synchronous motor (ORC-BPMSM), a decoupling control strategy based on the least square support vector machine (LS-SVM) generalized inverse is proposed. Firstly, the basic structure and working principle of the ORC-BPMSM are introduced, and the mathematical model of torque and suspension forces are established. Secondly, the ORC-BPMSM system is proved reversible by establishing mathematical models and reversibility analysis, then the pseudo-linear subsystems are formed by connecting the generalized inverse system, which is identified by the LS-SVM, with the original system. Furthermore, additional closed-loop controllers are designed to improve the stability and robustness of the pseudolinear subsystems. Finally, the proposed method based on LS-SVM generalized inverse is compared with traditional inverse system method by simulations and experiments. The simulation and experiment results show that the proposed control strategy has good performance of decoupling and stability.

This paper presents a dual-polarized crossed-dipole antenna with high isolation and wide-beam radiation. The antenna comprises two orthogonal printed dipoles with single-ended and differential feeds, which are collocated on a square ground plane. The single-ended feed dipole is built on the peripheral sides of a two-layer substrate, and it is fed by a Г-shaped stripline sandwiched between the substrate layers. The differential-feed dipole is built on a single-layer substrate, i.e., the differential feed with a Π-shaped microstrip-line, and the dipole arms are printed on the top-side and back-side of the substrate, respectively. The high isolation feature is achieved by exploiting the symmetry of the design with one pair of differential feeds. The beamwidth is significantly broadened by incorporating parasitic monopole elements while keeping the design symmetrical. A realization of the design concept for the 5G NR n78 band (3.3-3.8 GHz) has been optimized, fabricated, and tested. The measured results demonstrate an impedance bandwidth of 28.6% (3.0-4.0 GHz) and port-to-port isolation of > 40 dB. Furthermore, the antenna achieves a peak half-power beamwidth of 150°/168° in the E/H planes, and a cross-polarization level of < -30 dB at the broadside direction. These features make the proposed antenna a good candidate for the 5G and in-band full-duplex applications.

In this paper, we propose a quadruple band-notched ultra-wideband (UWB) antenna with a novel virus-mimicking structure. The proposed antenna is fed by coplanar waveguide in the FR4 material. It has a compact size of 27 × 29 × 0.8 mm³. In order to reject narrowband signal interference in ultra-wideband communication, the desired notches in WiMAX (3.3-3.6 GHz), WLAN (5.1-5.8 GHz), downlink X satellite communication system (7.25-7.75 GHz), and ITU 8GHz band (8.025-8.4 GHz) are realized. Except for these, impedance bandwidth of the designed antenna is less than -10 dB from 2.5 GHz to 15 GHz, with average gain of 3 dBi. At the same time, it basically meets the omnidirectional requirement. With low profile and compact structure, the proposed antenna can be integrated into the ultra-wideband system, which can meet the requirements of ultra-wideband communication and improve the anti-interference ability of ultra-wideband communication.

This paper proposes a hybrid excited permanent magnet vernier motor for low-speed and high torque applications in electrical drive. Traditional PM vernier motors are with PM excitation field, and the air-gap magnetic field density is hard to adjust, which limit the wide speed range of PM motor. The hybrid excitation method is proposed in the PM vernier with excitation windings set in the region between modulation pole pieces. With the finite analysis method, the basic structure and the working principle of the proposed motor are introduced, and the low-speed and high-torque characteristics with wide speed range are revealed. Then, the drive control system of the motor is designed and applied with the prototype motor. Finally, the experimental results verify the reliability and effectiveness of the design theory and simulation results.

This paper presents a comparative study that was done using genetic algorithm, improved particle swarm optimization and the hybrid technique genetical swarm optimizer approaches for the design of one-dimensional photonic crystal selective filters. The three evolutionary methods for synthesizing the geometrical parameters of a fiber Bragg grating structure from its layer thicknesses are proposed and demonstrated. The synthesis of the mono-band 1-D PhC selective filters is designed as a mono-objective problem, and these 1-D PhCs are composed of alternate Si and Air layers with thicknesses on the micron scale. The main contribution of this paper is formed by the solution to this kind of problems. According to the literature, this hybrid methodology genetical swarm optimizer has not been dealt with before, when 1-D PhCs selective filters are considered. Comparison of the GA, IPSO and GSO for the selected set of examples revealed an improvement of paramount importance in terms of error lowering and the number of iteration cycles diminution.

A quad-band (3.5, 5.8, 7.5 & 8.08 GHz), low profile, low Specific Absorption rate (SAR), and circularly polarized (3.5, 7.5, 8.08 GHz) wearable textile antenna (50x30x1 mm³) integrated with a triple-band zero reflection phase Artificial Magnetic Conductor (AMC) surface is presented. The designed standalone antenna exhibits low SAR with 10 mm separation for 0.5 W input power and radiation performance with a gain of >5 dB and Front to Back Ratio (FBR) (<10 dB) at all operating frequencies. The AMC unit-cell is synthesized using PDMS (Polydimethylsiloxane) with footprint of 20×20×1 mm³ to operating at 3.5, 7.5, and 8.08 GHz respectively with in-phase reflection. The designed 3×3 AMC reflector is integrated to improve the radiation performance of the designed antenna with gain to >7 dB, FBR to >10 dB, and withstanding low SAR at increased input power compatibility at separation (d=3 mm) from the body surface. The designed AMC transforms the radiation pattern from omnidirectional to directional with improved FBR, reduced back radiation with low SAR (<0.504 W/kg). The proposed AMC integrated antenna also providing mechanical feasibility in terms of handling the frequency detuning due to bending and the human-body loading feature makes it suitable for wireless body area networks (WBAN) applications.

Air compressors are widely used in various industrial fields. The motor of air compressor requires high power and high speed. This paper focuses on the structural design and loss analysis method of highspeed permanent magnet synchronous motor in air compressor. The structure of motor is designed. The key parameters are calculated. The influence of structural parameters on motor loss is analyzed. The analytical and design results are verified by finite element method (FEM). Finally, the prototype of motor has been manufactured. The performance of the motor is verified on the prototype.

A small ring antenna working at 2.45 GHz was designed in this paper, a small disk-coupled structure was applied to feed an inner-hole-biased ring patch, contributing to not only improving the impedance characteristics of the antenna but also reducing the size. The simulation results show that the designed patch area is only 70.7% of that of the traditional circular microstrip antenna on the premise of ensuring good bandwidth and gain performance; the -10 dB bandwidth of S₁₁ parameter is 62 MHz; the gain of the maximum direction is 7.11 dB; and the circular polarization of the antenna is also realized. This design has also been compared with several conventional designs, It is proved that the antenna has good comprehensive performance, and the antenna feed structure is simple, easy to process, very conducive to engineering applications. Finally, the feasibility of this technology was verified by contrasting the measured data with the simulation data.

In this paper we present a high pass filter based on half mode substrate integrated waveguide HMSIW technology dedicated to the transmission of microwave signals range from 6 GHz to 18 GHz. The taper is used for microstripe to SIW transition. We designed SIW line transmission using CST and HFSS simulators on a Rogers RT5880 substrate with dielectric constant of 2.2 and thickness of 0.508 mm, and we used the half mode technique for miniaturizing the filter size and achieving a size reduction about of 50%. The fabricated filter size is 60 x 12 mm². The lower measured return loss is about -51 dB. We compared the simulation results with measurement ones for validating our proposal. Good agreement between CST, HFSS and measurement results is observed.

In this paper, a novel low-profile direct feed antenna element is proposed to work across the mm-wave frequency band for 5G smartphone applications. The antenna covers the frequency band from 25-32 GHz achieving a wide fractional bandwidth of 24.5%. Contrary to most of the previously reported designs, the proposed antenna has a low-profile single-substrate structure and uses a conventional corporate feed. To improve the overall gain, a 16-element antenna array is formed based on the proposed antenna element. The total realized gain of the array is 15 dBi, and its size is 63×10×0.64 mm³ which fits inside a smartphone chassis. To validate the idea, a prototype is fabricated and measured. A study is also conducted, through simulations, on the beam steering capabilities of the antenna array using digital phase shifters. Having a simple structure and good performance makes the proposed antenna array an excellent candidate for 5G smartphone applications.

A dual-band dual-polarized dipole antenna with an artificial magnetic conductor (AMC) reflector is proposed, which can be applied in 5G base stations. The antenna consists of a pair of ±45° crossed dipoles and a wideband AMC reflector. By adopting arrow-shaped dipoles and introducing slots, dual-band characteristic is achieved. The AMC is designed to operate with 90° reflection-phase bandwidth of 2.1-3.9 GHz (30%). Compared with using traditional reflector, the profile height can be reduced from 0.25λ₀ to 0.11λ₀ (where λ₀ is the free-space wavelength at 2.6 GHz). The measurement results show that the impedance bandwidth with |S₁₁| < -14 dB is about 15.5% (2.44-2.85 GHz) and 18.6% (3.17-3.82 GHz), covering the Sub-6 GHz bands. The average gain is 8.5 dBi in the lower band and 8.2 dBi in the upper band. At 2.6 GHz and 3.45 GHz, the half-power beamwidth of the antenna is 77° and 80°, respectively. In the two bands, the port isolation of the antenna is more than 28 dB, and the cross-polarization level is less than -20 dB.

A model predictive control method for permanent magnet synchronous motor based on parameter identification and dead time compensation is proposed to solve the problems of poor parameter robustness and large current errors. In this method, the prediction model is firstly established based on the mathematical model of the permanent magnet synchronous motor. After that, the current error caused by the parameter change in the prediction model and the current harmonics caused by the dead time effect are basically analyzed theoretically. Then, the adaptive linear neural network algorithm is proposed to identify the motor parameters and applied to the prediction model, and the harmonic components are filtered out using the adaptive linear neural network algorithm. The recursive least squares algorithm is used to quickly update the system weights to improve the dead time compensation control effect. Finally, the effectiveness and correctness of the proposed algorithm are verified on the experimental platform. The experimental results show that the predictive control method of permanent magnet synchronous motor model based on parameter identification and dead time compensation can effectively reduce the current error of the control system and accelerate the dynamic response of the speed.

A wideband and widebeam magneto-electric (ME) dipole antenna is designed in this paper. Based on the conventional magneto-electric dipole antenna, a bent vertical metal plate is added to the electric dipole, and the impedance bandwidth (IBW) and beamwidth of the antenna are widened together. Inclined metal walls are added on both sides of the metal ground to improve the gain at high frequency and make the antenna gain more steady in the operating bandwidth. To further broaden the IBW of the antenna, the conventional Γ-shaped feed is changed into a branch structure. The IBW of the finally designed antenna reaches 56.8% (2.91-5.22 GHz). In the whole operational bandwidth, the radiation pattern in E-plane realizes the half power beam width (HPBW) of more than 110°, and the H-plane radiation pattern realizes the HPBW of more than 160°. The maximum width of E-plane HPBW is 175°, and the maximum width of H-plane HPBW is 229°.