This paper presents the design of a Super Wideband (SWB) antenna with enhanced bandwidth for microwave application with a detailed parametric study of the methods used to enhance the bandwidth of the conventional antenna. The proposed SWB antenna has emerged from a traditional circular monopole antenna by experimenting with the inscribed fractal structure with a tapered feed line and partial ground plane with blended corners and achieved a super wideband frequency range from 2.31 GHz to 105.5 GHz with a fractional bandwidth 192.1%, Bandwidth Dimension Ratio (BDR) 2154.88. The antenna has a relatively small electrical dimension i.e. 0.33λ₀x0.27λ₀, where λ₀ corresponds to the lower-end operating frequency and exhibits good gain and efficiency characteristics. In order to observe the signal correlation of the proposed antenna, the time domain analysis using similar antennas in face-to-face and side-to-side scenarios has been performed using the EM simulation tool CST-STUDIO. The simulated gain varies from 1.28 to 9.35 dBi. The proposed antenna can be used for S, C, X, Ka, Ku, V and W bands for microwave and millimetre wave applications. The simulated and measured results of the proposed antenna exhibit a good agreement.

Aiming at the problem of excessive torque ripple of switched reluctance motor (SRM), a three-interval PWM duty cycle adaptive control strategy is proposed in this paper. The method changes the PWM duty cycle to adjust the voltage across the windings according to the torque error, divides the interval according to the inductance linear model, and adapts to different PWM duty cycles in different intervals, different speeds, and different torque errors. And the optimal PWM duty cycle group under different rotation speeds is obtained by trial and error, and this duty cycle group is used as the control method to adapt the PWM duty cycle group. Finally, through Matlab/Simulink simulation and motor platform experiments, the three-interval fixed PWM duty cycle control strategy and the three-interval PWM duty cycle adaptive control strategy in this paper are compared. The results show that the three-interval PWM duty cycle adaptive control strategy proposed in this paper has a good torque ripple suppression effect in a wide speed and wide load range.

An ultra-wideband (UWB) antenna with dual band notched characteristics verified by characteristic mode analysis (CMA) is presented. The intended UWB radiator is etched on a Rogers RT5880 substrate with a size of 29×35×0.764 mm³, operating over a spectrum of 2.66-14.86 GHz with a fractional bandwidth (FBW) of 139%. Dual notched bands at WiMAX (3.01-3.63 GHz) and WLAN (4.48-5.85 GHz) are achieved by embedding L-shaped stubs in the notched rectangular patch. In addition, the two notched bands of the reported antenna are verified by using characteristic mode analysis (CMA) in terms of modal significance (MS) and characteristic angle (CA). The reported antenna's simulated and tested results are well matched to obtain S₁₁, VSWR, stable radiation patterns, a stable peak gain of 2.65 to 3.6 dBi and the maximum radiation efficiency of 97.86% in frequency domain, which makes the intended radiator suitable for portable UWB applications.

A novel dual-band filter power divider (DB-FPD) with controllable transmission zeros (TZs) is designed using a slotline multimode resonator (SLMR) in this letter. Using the stub loading technology, each resonator mode of the SLMR can be easily controlled. Accordingly, a dual-band bandpass filter is realized. Four TZs are generated due to the loaded stubs on the SLMR and feeding network, which can improve the out-of-band selectivity. Finally, without introducing additional circuits, a DB-FPD with good performance is realized. For verification, a prototype operating at 2.01 and 4.79 GHz is fabricated and measured. The measured results are basically consistent with simulated ones. The 3-dB fractional bandwidths are 29.7% (1.72~2.32 GHz) and 7.99% (4.58~4.96 GHz), respectively, and the isolation in each band is better than 14 dB.

A flux weakening (FW) control method of leading angle for a permanent magnet synchronous motor (PMSM) based on active disturbance rejection control (ADRC) is proposed to solve the problem of large fluctuation of speed, current, and torque in the control process. Firstly, according to the mathematical model of PMSM and its voltage and current constraints, the leading angle FW control algorithm is introduced. Then, according to the ADRC theory and the mathematical model of PMSM, the speed loop ADRC and current loop ADRC are constructed. The controller parameters are combined with the control bandwidth, and the parameter variation ranges are obtained by analyzing the stability of the control system. Finally, the proposed ADRC methods are combined with the leading angle FW control method to realize the ADRC leading angle FW control for PMSM, and the proposed method is verified on the experimental platform. The experimental results show that the proposed method has less speed, current, and torque fluctuations than the proportional integral (PI) controller method, which can effectively improve the motor control performance. At the same time, the controller parameters are combined with the bandwidth, which is convenient for practical engineering application.

This paper reports a novel, cost effective, and compact ultra-wideband (UWB) antenna for applications in an unlicensed-frequency band of 3.1-10.6 GHz. To achieve the UWB operation, a novel concept of annular shapes, circular slot combinations, and partial ground is employed. Furthermore, the proposed antenna with novel configuration occupies an attractive size of only 18×12 mm² which allows compatibility with portable UWB application devices. This flower-horn shaped UWB antenna is printed on a cost-effective FR-4 substrate, which exhibits a dielectric-constant of 4.4 and a loss-tangent of 0.019. The fabricated prototype is experimentally tested, and measured results validate the design approach of presented UWB antenna. The measured results confirm its UWB characteristics covering 3.1-11.2 GHz with S₁₁ ≤ -10 dB. Also, a maximum peak-gain of 5.05 dBi at 9 GHz and a minimum radiation-efficiency of 94.35% are noted in the full operating-band. A good agreement has been obtained between the simulated and measured results in terms of reflection-coefficient, gain, radiation-efficiency, radiation patterns and group delay which confirm the suitability of suggested small printed antenna for the intended UWB applications.

In this paper, a dual-band ultra-wideband conformal antenna for Wireless Capsule Endoscopy is proposed. The antenna uses polyimide as a substrate of side wall to achieve conformality, leaving space for other components of the Wireless Capsule Endoscopy. The feeding network of the conformal antenna utilizes the circuit characteristics of Complementary Split-Ring Resonator to achieve dual-band operation at 1.4 GHz and 4.0 GHz. Based on the principle of wideband characteristics of spiral antennas, the conformal antenna radiation structure is improved. A short-pin is loaded at an appropriate position to improve the impedance matching of the antenna and achieve ultra-wideband without changing the resonant points of the antenna. The operating bandwidth of the antenna can reach 30.3% (1.20~1.63 GHz) and 53.3% (3.33~5.75 GHz), respectively. In addition, the antenna is placed in different simulation models to verify the stability of its operation. Minced pork is used to verify effectiveness of the conformal antenna. The measured results show that the proposed antenna is suitable for capsule endoscopy.

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.