In view of the problems of excessive magnetic flux leakage of the traditional permanent magnet fault-tolerant vernier rim-driven motor, low utilization rate of permanent magnets and high price of permanent magnet materials, this paper proposes a flux-concentrating consequent-pole permanent magnet fault-tolerant vernier rim-driven motor structure. Firstly, combined with the magnetic field modulation theory, the no-load air gap magnetic density of the motor is analyzed, and the working principle of the multi-harmonic operation of the motor is explained according to the harmonic analysis. Secondly, parametric modeling is used to screen the critical structural parameters that can significantly affect electromagnetic performance of the motor, and the response surface method and sensitivity analysis are used to rank the sensitivity of the critical parameters. Then, the high-sensitivity parameters are first subjected to multi-objective optimization, and then adjusted according to the low-sensitivity parameters. Finally, the air gap magnetic density, back- EMF, cogging torque and permanent magnet numbers of the motor before and after optimization are compared and analyzed by finite element analysis. The results show that the flux-concentrating consequent-pole permanent magnet vernier rim-driven motor has higher torque density, less torque ripple and higher utilization of permanent magnets.
This research article presents an innovative design of a textile-based microstrip patch antenna with a metasurface for medical applications. The antenna is designed to operate at a frequency of 2.4 GHz, which is the frequency of the Industrial, Scientific, and Medical (ISM) band, to minimize the Specific Absorption Rate (SAR) in the human body. The design includes an Electromagnetic Band Gap (EBG) that is placed above a metasurface, which is made up of a periodic array of I-shaped structures. A foam layer is placed between the EBG and the antenna to improve performance. The use of textile-based materials in the antenna allows for flexibility and comfort when it is mounted on the human body. The integration of the metasurface in the antenna design allows for a more efficient transfer of energy from the antenna to the surrounding tissue, resulting in a reduction in the amount of energy absorbed by the body. The simulation of the antenna design is carried out using Computer Simulation Technology (CST), which provides accurate results for the performance of the antenna. After the implementation of the EBG array, the gain of the antenna is improved, resulting in better performance. The proposed antenna design achieved a SAR value of 0.077 W/kg over 1 gram of thigh tissue, which is well below the safety limit set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This implies that the integrated design of the antenna can be safely used inmedical applications.
This article presents the recent advancements in utilizing metamaterials for the development of high-performance antennas in 5G communications. The focus is on negative refractive index metamaterials composed of two unit cells: a complementary infinite split ring resonator (CI-SRR) and a Hilbert fractal embedded in the ground plane. These metamaterials enable antenna size reduction while enhancing performance. The proposed antenna metamaterials offer improved antenna characteristics and precise control over physical dimensions, facilitating the creation of highly efficient devices with miniaturized antennas. Additionally, an antenna array 1×3 is incorporated to further enhance performance. The antenna design has a compact size of 40×33×1.57 mm2 and is fabricated using Rogers RT/Duroid 5880 material. The final broadband antenna exhibits a wide impedance bandwidth of 12.71% at 32 GHz, accompanied by a gain of 10.5 dBi. The comparison between wave concept iterative process (WCIP) calculations and measurements shows good agreement. The fabricated structure is thoroughly analyzed using a Keysight PNA network analyzer, demonstrating its successful operation and suitability for broadband applications.
An improved model-free nonsingular fast terminal sliding mode control (IMFNFTSMC) algorithm based on super-twisting extended sliding mode disturbance observer (STESMDO) is proposed to address the problems of control performance degradation and system failure of surface-mounted permanent magnet synchronous motor (SPMSM) under complex operating conditions. Firstly, the mathematical model of SPMSM under parameter ingestion is established; secondly, a novel hyperlocal model is proposed to combine with variable exponential approach law and the nonsingular fast terminal sliding mode (NFTSM) surface to design the speed-loop IMFNFTSM controller to accelerate the system convergence while reducing the sliding mode jitter. To enhance the control accuracy, the super-twisting extended sliding mode disturbance observer (STESMDO) is designed to estimate and feed-forward compensate the system disturbance. Finally, the effectiveness and superiority of the designed algorithms are demonstrated by comparing the proposed method with PI and the conventional model-free nonsingular fast terminal sliding mode control algorithm (MFNFTSMC) through simulations and RT-Lab experiments.
Currently, the inspection and verification of vehicle-related information are done by police inspectors using camera-based systems or manually. Though integrating video technology is more advantageous than manual operation, they do not perform accurately due to bad weather or driving styles. This paper presents the design of a compact, durable, battery-free, UHF RFID tag with enough memory to carry necessary information for automatic identification of traffic law enforcement applications. The vehicle owner can also be alerted when the tag is detected due to the visual indication facility. This tag's novel feature includes adapting a modified T-match structure to match the highly capacitive impedance of the chosen RFID sensor chip, i.e. Farsens Rocky100. In contrast to existing designs, the proposed tag contains no extra lumped components that necessitate an external impedance matching circuit. Instead, the input impedance was matched using an advanced T-match topology and by optimizing the antenna's geometrical features. Simulations were done in Ansys HFSS (High-Frequency Structure Simulator) whereas the dimensions of all the printed elements were fine-tuned using parametric optimization. The tag was fabricated on a low-cost FR4 substrate and measured. The tag with an overall size of 110 × 25 × 2.4 mm3 can be detected by a conventional UHF RFID reader within a range of about 0.2 m-1 m. Due to the loop configuration, the tag exhibits a confined detection range while operating well within short ranges.
In recent years, the non-embedded uncertainty analysis method has been widely used in the field of Electromagnetic Compatibility due to its wide application range. In this paper, from the perspective of the practical application of uncertainty analysis methods, four non-embedded uncertainty analysis methods are applied to the worst-case estimation of Electromagnetic Compatibility, which are the Monte Carlo Method, Stochastic Collocation Method, Stochastic Reduced-Order Models, and Kriging surrogate model method. The performances of four uncertainty analysis methods in terms of computational accuracy, computational efficiency, and ability to deal with complex problems are compared in detail by using the parallel cable crosstalk prediction example in the existing literature and the uncertainty analysis example of self-constructed optimization test function, which provides a theoretical basis for uncertainty analysis method to guide the actual Electromagnetic Compatibility design.
This study describes a noncontact low-cost X-band sensor system for determining the soluble solid content (SSC) of a sugar solution. The system adopts a transmission signal technique with two frequency pairs (10.2 GHz paired with 10.4 GHz and 10.2 GHz paired with 10.6 GHz) from three transceiver modules. Each module has a microstrip patch antenna, mixer circuit, and dielectric resonator oscillator. To simplify the transmission power frequency of each frequency pair, the frequency is down-converted to an intermediate frequency (IF) signal using a frequency mixer. The IF signals are then compared using a gain and phase detector to find their magnitude ratio and phase difference. The measured SSC-level data are randomly divided into three datasets and input to an artificial neural network (ANN) for training. The training output is the SSC level in Brix degree. The proposed ANN structure comprises four input nodes, eight hidden nodes, and four output nodes, affording low complexity and resource savings while providing 92.98% accuracy. Therefore, the proposed low-cost sensor system can achieve precise decision-making and real-time measurement.
Doubly Salient Singly Excited Machine (DSSEM) inbuilt with the features as high torque density, high speed density, compactness, low maintenance, but the machine reduces its application due to its demerits as torque ripple. This study enhances the performance of switched reluctance motor (SRM) in the track of electromagnetic and mechanical characteristics. A 290 Volts, 10 Amps, 3000 rpm, 4 N-m SRM undergoes finite element (FE) characterization in the view of parameters like torque ripple. In the regard of torque characterization, the ripple torque is estimated under rated condition. FE analysis gives accurate results by 2D analysis. Torque ripple is the main concern in electrical machines, because these two are responsible for producing harmonics, vibration, and noise. So, a novel machine is designed to reduce the torque ripple content. The losses are considered as heat generation as a source of temperature rise in a motor, and the heat distribution is analyzed. The experimental setup is arranged to evaluate the simulation results with the current profile of FE analysis and prototype for verification.
This paper presents a multiband flexible wideband coplanar waveguide (CPW) wearable slot antenna for biomedical and Internet of Things (IoT) applications. The proposed antenna comprises an elliptical patch with a slot designed on top of a thin and flexible polyimide substrate of thickness 0.1 mm. CPW feeding with slotting on the ground and a protruding microstrip from the ground on one side of the patch is used to have resonance at multi-frequencies for the proposed antenna design. The measured results show that the developed antenna resonates at 2.81 GHz with an impedance bandwidth of 0.8 GHz (2.23-3.2 GHz) and at 4.43 GHz, 5.96 GHz, and 9.38 GHz with an impedance bandwidth of 6.7 GHz (3.5-10.3 GHz). The proposed antenna is simple and portable to mount on any part of the human body and obtains justified specific absorption rate (SAR) values. The prototype of the suggested antenna underwent the fabrication process. A comparison of the antenna parameters was carried out, and there was a reasonable correlation between the simulation and measured results. The proposed antenna is a good contender for Wireless Body Area Networks (WBANs) and IoT applications.
Owing to the principle of relativity, the present state of knowledge explicitly allows Maxwell's equations to be solved not only in the rest frame of an electromagnetic transmitter but also directly in the rest frame of the receiver without use of the Lorentz transformation and the Lorentz force. Recently, such a calculation was first performed for the Hertzian dipole. The analysis of the resulting formula breaks new scientific ground and indicates that Maxwell's equations predict that electromagnetic waves in vacuum propagate at the speed of light, notably for each receiver, even when these receivers have relative velocities with respect to each other. Although this paradoxical phenomenon was expected, the finding that Maxwell's equations nevertheless predict a classical Doppler effect was unexpected and indicates inconsistent or not yet fully understood aspects of canonical Lorentz-Einstein electrodynamics consisting of Maxwell's equations, Lorentz force and Lorentz transformation.
This study presents a pioneering curved antenna design that is seamlessly integrated into Wireless Capsule Endoscopy (WCE) devices. The proposed antenna features a miniature height of 25 mm, a radius of curvature of only 5.5 mm, and a conductive line width of up to 2 mm, making it an ideal fit for use in compact WCE applications. The antenna is specifically designed to operate in the ISM5800 band and achieves outstanding performance metrics, such as an S11 of -10 dB and a Gain of 5.8 dBi. To evaluate the safety of our design for human usage, we conducted an investigation of the specific absorption rate (SAR) of the Hugo Model antenna in various positions for ISM5800 and compared our findings to the safety limits specified by the Federal Communications Commission (FCC) standards. Our results confirm that the proposed antenna design meets the safety requirements for wireless communication systems in biomedical applications, thereby demonstrating its potential for clinical use.
A Koch Snowflake fractal structure embedded octagonal patch antenna with hexagonal split ring for Ultra-Wide Band (UWB) and 5G applications is proposed. In this proposed design, Koch Snowflake pattern is chosen for embedding into the octagon-shaped patch antenna, which tentatively develops a miniaturized cross-sectional area in the radiator and introduces wide resonance with enhanced gain. A hexagonal split ring is introduced into patch to handle negative refraction in the radiations and to initiates self-inductance and capacitance which manages the impedance matching. Here, a co-planar waveguide (CPW) is employed for transferring electric field into patch and a lumped port is used to induct field between patch and ground. The two slots S1 and S2 made on ground are supportive in obtaining wider resonance. The Substrate used in the proposed design is Flame Retardant 4 (FR-4), which is utilized in various electronic modules. The dielectric constant and loss tangent of FR-4 substrate are εr = 4.4 and δ = 0.02 respectively. The complete dimensions of the proposed model are 25 x 30 x 1.6 mm3. The simulated antenna is designed using Ansys High Frequency Electromagnetic Simulation Software 17.2 (HFSS 17.2). The simulated design features a Peak Gain of 6.3 dBi and Fractional Bandwidth (FBW) of 168% (Frequency ranges from 2.6 GHz to 28.9 GHz) with Bandwidth ratio of 11.1:1. Also, the designed antenna is fabricated using Milling method and the fabricated prototype offers Fractional Bandwidth (FBW) of 168% (Frequency ranges from 2.4 GHz to 28.5 GHz) and gain of 6.27 dB which are tested and measured using Microwave analyzer and anechoic chamber. Thus, the proposed antenna covers the resonance which includes S-band, C-band, X-band, Ku-band and K-band. Also, it completely wraps the UWB spectrum range (3.1 GHz to 10.6 GHz), 5G (Sub-6 GHz band) Frequency Range 1 (FR 1) spectrum, and most deployed 5G mm-wave Frequency Range 2 (FR2) spectrum (24.25 GHz to 29.5 GHz).
In the current system of wireless communication, Users expect devices that are lightweight and offer broad bandwidth as well as a high data transmission rate. Developments in data speeds, bandwidth, ultra-low response times, excellent dependability, considerable accessibility and improved device-to-device connectivity are what have driven wireless systems toward 5G. These 5G wireless systems require small and efficient antenna designs. This work proposes a 5G mm-wave quadrilateral slotted defected ground structure (QSDGS) including a wideband monopole antenna (WMA) for n259 and n260 5G mm-wave bands. Here, the DGS was modelled using two quadrilateral slots on a ground plane. An inset feeding technique and multiple slots were employed to patch. This structure consists of a DGS-loaded slotted antenna patch mounted on a Rogers/RT Duriod 5880 (εr = 2.2, loss tangent = 0.0009) with dimensions of 12x11x0.9 mm3 (1.42λgx1.30λgx0.10λg). This embedded antenna radiating structure resonates from 35.5 GHz to 44.7 GHz, giving an impedance bandwidth of 9.2 GHz (24.2%), with a centre frequency of 38 GHz. 9.48 dB was the peak gain, and 83-94% efficiency was obtained over the wide band. Based on the extracted data from the proposed antenna, it was found that the antenna is capable of covering the 5G NR n259 and n260 with significant gain, bandwidth, and efficiency. Thus, the antenna has the ability to be considered a possible contender to be used in 5G wireless applications using mm-wave frequencies. A good agreement can be seen here between simulated and measured return losses.
This paper presents the design, fabrication, and measurement results of a flexible folded dipole rectenna for 5G technology. The proposed rectenna is a single-sided structure fabricated on a flexible Kapton substrate with a maximum RF to DC conversion efficiency close to 53% for an input power of -9 dBm at 3.5 GHz with 3-KΩ. Moreover, the measured results show that the conversion efficiency is above 40% across a broad range of input power levels (from -14 to -8 dBm). The paper discusses the prototype's design and simulation results, fabrication steps, and measurement results. The proposed rectenna is compact, low-cost, and flexible, making it suitable for wearable applications.
This paper presents the total gain and directivity control with port excitation in a 4×4 hexagonal split-ring resonator (H-SRR) MIMO antenna for dual-band operation in 2.4/5.2 GHz bands. The MIMO antenna is shown more than 15 dB isolation between antenna elements placed orthogonally, and a spacing was introduced between them to achieve higher isolation in the first proposed design, then, a Z-shaped structure of specific dimensions was inserted to further improve the isolation between antenna elements. The simulated and measured return losses and transmission coefficients confirmed the improved performances for impedance bandwidth and isolation. The gain, axial ratio, and radiation pattern performances of the 4×4 H-SRR MIMO antenna are studied by exciting different port combinations of the four ports of the proposed antenna. A wide range of gain and axial ratio variations are observed on exciting single, dual, triple, and quad-ports of the proposed MIMO antenna and discussed using the radiation patterns. Also, various MIMO parameters, ECC < 0.04, TARC < -10 dB, MEG < -6 dB, DG < 10 dB, and CCL < 0.4 bits per second per Hz, are found in the 2.4/5.2 GHz bands, which confirms the applicability of proposed H-SRR MIMO antenna with polarization diversity.
In this paper, a compact antenna with wideband and wide beam is proposed. It is composed of a rectangular patch etched on a substrate, a feeding probe, two metal columns, and a ground plane. By inserting air gap between the substrate and the ground, as well as using the coupled feeding, wide impedance bandwidth is obtained. By inserting two metal columns on the two sides of the patch for inducing longitudinal current, the HPBW of the antenna in the operation bandwidth can be widened. Design evolutions are provided for the proposed antenna, and main parameters are investigated for obtaining the adjusting rules. For validation, a prototype operating at 5.8 GHz is fabricated, where the dimension is only 0.31λ0 × 0.11λ0 × 0.11λ0. Measurement results show that a fractional bandwidth of 24% is achieved for |S11| < -10 dB. In this bandwidth, the measured gain is larger than 2.5 dBi with a maximum gain of 3.5 dBi. At E-plane, the measured HPBWs are in the range of 130°~190°, and the values are around 120° at H-plane.
This article presents a simple method to introduce multiple Transmission Zeros in the stopbands of a triple passband Chebyshev filter and also suppress the spurious bands below a satisfactory level, so that it can be treated as a Quasi-Elliptic filter. A pair of Stub Loaded Step Impedance Resonators (SLSIRs) is used to produce the Chebyshev filter with central passbands at 2.5, 5.5, and 9 GHz. An asymmetric Non-Resonating T (NRT) structure is implemented on each of the SLSIR to achieve the improved skirt selectivity. Each non-resonating structure produces three Transmission Zeros (in total six). In addition to the satisfactory stopband performances, the Quasi-Elliptic triple band filter produces insertion losses of |0.4|, |0.6|, and |0.7| dB at three centre frequencies respectively. Simulation of the proposed filter is done using HFSS13 software, and to validate the simulation, a prototype is fabricated on an Arlon AD250 (Dielectric Constant 2.5, height 0.76 mm) substrate.
This paper presents a 3 dB compact Ultra-Wide-Band (UWB) Substrate Integrated Gap Waveguide (SIGW) based hybrid coupler suitable for 5G mm-wave applications. It is a key component in signal processing for wireless communication. It provides a way to control the power distribution of the signal along different ports. It could be used to achieve beamforming and adaptive antenna system. The design steps started with implementing a unit cell of the gap waveguide structure satisfying the required bandwidth of the coupler. A supercell is then implemented. A network of complete ridges is constructed. A further step is to design a coupling section which achieves the required power distribution along the coupling and isolated ports. This coupling section is implemented using a novel approach of inserting an elliptical slot with variable major and minor axes with a certain orientation that achieves the standard performance of a 3 dB directional coupler with 90° ± 5% phase shift. For precise adjustment of this amplitude and phase, vias are further added perpendicular to the major axis of the slot. Its dimension and location have to be optimized. The Finite-Integral-Time-Domain (FDTD) analysis method is adopted (CST Microwave Studio). In addition, another novel approach is developed on this coupler such that the transition and gap layer is implemented on the same PCB layer, which saves the number of layers to only two layers compared to the usual three layers used in literature. Also, using SIGW technology saves the collapse of the top ground layer on the ridge structure, and only plastic pins are used to fix the two layers. The proposed coupler is fabricated and tested, and the results show that it serves the majority of frequency bands employed in 5G systems in the USA and Canada.
This paper presents a novel dual-band dielectric electromagnetic band gap (EBG) antenna that operates in both wireless local area network (WLAN) and X-band satellite applications. The proposed structure comprises new double EBG layers placed on the top face and fed by a coaxial probe. The design and parametric analysis of the band gap structure have been performed using Ansys HFSS simulation software. The measurement results are found in good agreement with the simulation results, indicating that the proposed antenna design is a promising solution for dual-band applications. As a result, we have found significant enhancement in gain up to 8.1 dB and 9.3 dB at both frequencies of 5 GHz and 9.8 GHz.
Fabrication of a non-planar helical antenna while maintaining mechanical stability and durability is always challenging. Moreover, impedance matching is an issue for helix-type antennas. To ease the fabrication challenge, the advantage of additive manufacturing is utilized. For achieving the self-matching, radiating spiral conductors in the forms of a strip and thick wire are used as two independent techniques. Consequently, a 3-turn hemispherical helical antenna (HHA) is chosen and analyzed by varying the width of the strip and the diameter of the wire. The better-performing HHA is again investigated including the effect of Poly-lactic acid (PLA) material-based supportive structure. The impacts of this extra support on antenna performance parameters are also investigated. At the initial step of fabrication, a 3-D printer is used to have the complete support structure. For ensuring the metallic part, copper strips and conductive paints are used as two different approaches. The measured data validates that both strip and wire-based HHA are self-matched. Circular polarization is obtained over wide frequency bands with axial ratio bandwidth (AR BW) of 35%. The maximum gain and beamwidths under 3-dB AR BW are 9.35 dBi and 118° respectively. The mechanically stable, low profile, and wideband circular polarization favored theuse of HHA in satellite communication.