In this paper, an analytical calculation of the magnetic field in a consequent-pole bearingless permanent magnet (PM) type motor with rotor eccentricity is proposed. The analytical method is based on the resolution of Laplace's and Poisson's equations. Due to the presence of consequent-pole, the general solution of the first-order for the vector potential distribution in the air-gap is presented considering the first harmonic. Here, the magnetic field distributions by the analytical method are compared with those obtained from finite element (FE) analyses. Then, the corresponding performances are quantitatively assessed by the finite-element method.

A three-box model, composed of a triangular memory polynomial, a look-up table, and a cross item among memory times, is proposed for power amplifiers. The model acquired good accuracy and linear effect and reduced the calculation coefficient. Moreover, the paper proposes the GRLS_IVSSLMS adaptive predistortion algorithm. This algorithm is based on the structure of indirect learning. This work uses 16QAM signal to drive a strongly nonlinear Doherty amplifier. Experimental results show that the proposed method is suitable for the adaptive predistortion of power amplifiers.

A novel miniaturized bandpass half-mode substrate integrated waveguide (HMSIW) filter which uses dual-iris coupling method to load complementary split-ring resonators (CSRRs) into HMSIW is proposed in this paper. By modifying traditional CSRRs through nesting method combined with step impedance structure, a nested stepped-impedance complementary split-ring resonator (NSICSRR) structure with higher equivalent capacitance and inductance of CSRR is obtained. Based on the traditional single-iris coupling method, a dual-iris coupling method is developed. And NSICSRR is loaded into HMSIW by using the dual-iris coupling method, which can reduce the resonant frequency of the structure. In order to verify the effectiveness of the technology above in realizing the miniaturization of HMSIW filter, a second-order HMSIW filter is designed and measured. It can be found in the measured results that the filter has the center frequency of 6.35 GHz, the 3 dB bandwidth of 690 MHz, the return loss of better than 14 dB within the passband, and the size of 0.0396λ_g². The experimental results are basically consistent with the simulation ones.

In order to design a robust passive temperature sensing tag that can operate over a wide temperature range, temperature-sensitive characteristic of UHF radio frequency identification temperature sensing chip and corresponding tags are studied. The devices under test include dipole tags with different antenna impedances. Simulation data, experiment design, system setup, measurement procedures, and test results are given. The results show that as temperature increases, the real part of chip impedance increases, and the absolute value of the imaginary part decreases, which are consistent with simulation data. In the full temperature range, the overall performance of sensing tags designed for high-temperature conditions is better than tags designed only for room temperature conditions.

A dielectric resonator (DR) based MIMO (Multiple Input Multiple Output) antenna with enhanced isolation is proposed in this letter. The proposed MIMO antenna consists of four hemispherical shaped dielectric resonator (HDR) radiating at 4.9 GHz. The isolation between two consecutive radiators is enhanced by rotating feeding line of one element at an angle of 180˚. The antenna is studied in terms of S-parameters, gain, envelope correlation coefficient (ECC), channel capacity loss (CCL) and diversity gain (DG). All the parameters are found to be within acceptable range. The proposed design is fabricated, and it is found that measured results are in good agreement with simulation.

This research presents a novel integrated multiband antenna system manufactured and tested for Smart Industries applications. The proposed system consists of a miniaturized planar antenna with multi-arms conceived to cover the most required frequency bands in industry 4.0 such as GPS Band, UMTS Band, ISM Band, LTE Bands, and WiMax Bands. The manufactured design was verified using Arduino programmable circuit board interfaced to SIM900 module and digital sensors for data collection. Depending on the commands received through the human machine interface (HMI) from the end-user, the developed algorithm within the Arduino controls the SIM900 to select the adequate wireless technology to transmit the data and thus reconfigures the antenna to radiate at the target frequency band. The proposed system is easy to deploy inside industrial machines and cost-effective for large scale use. The paper first introduces the main challenges and benefits of miniaturized low-cost antennas systems for Smart Industries and Internet Of Things. Further the parametric study and final dimensions of the design and simulation results are discussed. The proposed design is fabricated, and the measurements of the radiation pattern and return loss are performed. The antenna, with measured maximum gain up to 10 dBi and measured S₁₁ up to -20 dB, exhibits excellent performance for all the frequencies required in Smart Industries such as 1.6 GHz, 1.8 GHz, 2.3 GHz, 2.4 GHz, 2.6 GHz, 3.5 Ghz, and 5.8 GHz. The proposed antenna system was implemented and tested inside an industrial machine for Yogurt and Milk production and compared to existing commercial solutions. This study shows that the proposed antenna system is suitable for smart factories since it is miniaturized for internal integration, and it has self-frequency-adaptation and low power consumption, allowing the end-user to remotely control and monitor machines and smart devices.

A new compact broadband circular fractal antenna is presented to simultaneously cover the operations in S-, C-, X-, and Ku-bands. Fractal geometry of the radiator including an iterative circular patch with a square slot, a modified feed-line with step technique, and slot-loaded semi-circular ground plane is used to achieve a broad impedance bandwidth more than 151% from 3 to 21.5 GHz (|S₁₁|< -10 dB). The simulation results are verified by experimental measurements. Measured data are in good agreement with the simulated results. The frequency- and time-domain characteristics of the antenna including impedance matching, far-field patterns, gain, group delay, and fidelity factor are presented and discussed. The proposed broadband antenna features small size of 38×36×1.4 mm³ and nearly omnidirectional radiation patterns that make it excellent candidate for integration in broadband wireless communication systems.

In order to design differential phase shifters (DPS) from metamaterial-based transmission lines, research had a long tradition of usingbalanced transmission lines which are a particular case of metamaterials, specifically characterized byasimplified equivalent circuit model. This paper presents an innovative way of designing DPS metamaterials by exploiting metamaterial properties more widely, using both balanced and unbalanced cases to obtain a broader set of solutions. These solutions are acquired through the dedicated method this paper expounds, and conceived with the help of a new use of metamaterials. For the sake of ensuring time efficiency and implementation easiness of this design method for industrial purpose, the full wave parametric optimization is reduced to its minimum by exploiting as much as possible in analytic parametric study. This method is illustrated by an application of 180° DPS on C-Band (5-6 GHz). Three prototypes were fabricated, and the measurements show that the best case of DPS has less than 9° of phase error over the targeted 20% bandwidth, with a return loss less than -14 dB and insertion losses lower than 1 dB.

A patch antenna system operating in the 2.4-2.5 GHz ISM band is proposed for in-band full duplex applications. The proposed antenna consists of a patch antenna, a modified 180˚ hybrid, and a defected ground structure. Fabricated prototype results show a measured bandwidth of 100 MHz and an isolation of -75 dB at the center frequency with an isolation of at least -50 dB covering the ISM band 2.4 GHz-2.5 GHz. The design also has a spherical directional radiation pattern, low cross polarization, and reasonable gain values.

The output power of a magnetic coupling resonance wireless power transfer (MCR-WPT) system attains the maximum value at two frequencies splitting in an over-coupled region. To achieve suitable transfer characteristics, impedance compensation methods have been used in MCR-WPT domain. In securingthe constant output power and transfer efficiency in a constant frequency mode, a topology of the MCR-WPT system with two transmitting coils is employed. First, the circuit model is designed while evaluating the transmission characteristics. Second, when the two transmitting coils are placed into the transmitting loop, the main transmitter and sub-transmitter loops are created by sharing the same transmitter. The use of two transmitting coils to achieve a magnetic field superposition is investigated. Constant output power and transfer efficiency are then investigated in a constant frequency mode.Finally, the experimental equipment is designed. Experimental results confirm the effectiveness and robustness of the topology. Such a topology can be optimized for the transfer performance by itself and can achieve constant output power and transfer efficiency.If the distance between the two transmitting coils is appropriate and the receiving coil moves between the two transmitting coils, the fluctuation of the output power and transfer efficiency of the MCR-WPT system is less than 5%.

The propagation equation of a Lorentz-Gauss (LG) vortex beam in biological tissues is derived. The influences of the beam parameters and the biological tissues on the spreading properties of a LG vortex beam are investigated. The obtained results are interpreted numerically and shown that the LG vortex beam propagating through biological tissues with the stronger turbulence strength will lose the dark hollow center and evolve into the Gaussian-like beam more rapidly.

A practical coplanar waveguide (CPW) fed ultra-wideband (UWB) antenna with reconfigurable dual band-notched characteristics is proposed in this paper. A cup-shaped branch is added to the grounding plate and a step impedance resonator (SIR) added to the microstrip line, which realize notch characteristics in 5.1~5.9 GHz and 7~7.8 GHz bands and realize double notch function with good radiation direction characteristics. The antenna bandwidth is extended by using CPW feeding, ranging from 3 GHz to 16 GHz with the relative bandwidth of 137%. The notch band reconfigurability is realized by integrating three switches into the cup-shaped branch and SIR. In addition, the proposed antenna has a compact size of 24 mm × 32 mm × 1.5 mm and can provide omnidirectional radiation pattern, which is suitable for UWB communication applications.

In recent years, there has been more research on the use of photonic crystals PCs in the field of detection. The application of these materials as gas sensors seems very promising, because of their miniaturization and high spectral sensitivities. The aim of this work is to contribute to the design and study of a resonant microsystem based on one-dimensional photonic crystals for applications such as optical devices with high quality factor for detecting and measuring the concentration of gas in the air. Indeed, we have proposed a gas monitoring structure. This nanosystem is formed by an alternating stack of silicon Si layers and air with a resonant nanocavity in the middle. The numerical results show that the resonance peak that appears on the Photonic Band Gap (PBG) is caused by the creation of the nanocavity within the periodic 1D structure. This resonance peak can be used as a reference for real-time detection and environmental monitoring. In addition, we theoretically studied the relevance of these photonic systems and analyzed the effect of the intrinsic and extrinsic parameters of this device on the detection performance. We have also tried to improve the performance of such a device for the effect study of the inclination variation of the radiation incidence source on the selectivity of the detector.

Radar sliding window detection processes are often used in signal processing as alternatives to Neyman-Pearson based decision rules, due to the fact that they have a simpler receiver implementation and can often be designed to maintain a constant false alarm rate in homogeneous clutter. These detection processes produce a measurement of the clutter level from a series of observations, and compare a normalised version of this to a cell under test. The latter is an amplitude squared measurement of the signal plus clutter in the complex domain. It has been suggested by some authors that that there is sufficient merit in the approximation of the cell under test by a distributional model similar to that assumed for the clutter distribution. This is certainly the case when a Gaussian target is combined with Gaussian clutter, or equivalently a Swerling 1 target and exponentially distributed intensity clutter. The purpose of the current paper is to demonstrate, in a modern maritime surveillance radar context where the clutter is modelled by Pareto statistics, that such an approximation is only valid under certain limiting conditions.

In this paper, a W-band single-pole four-throw (SP4T) switch for multichannel high power transceiver chipset design is proposed based on a standard commercial 100 nm GaAs power pseudomorphic high electron mobility transistor (pHEMT) technology. The process used in this work is optimized for use in power amplifier (PA) design, resulting in larger drain electrode capacitance. In order to reduce the effect of large drain capacitance for switch design, a proper series capacitor is adopted. This capacitor can not only reduce the parasitic capacitance of the turn-off state transistor but also resonate with the parasitic inductance of the turn-on state transistor to improve the isolation. As known, the short stub is adopted to compensate the remaining parasitic capacitance. For verification, a prototype is fabricated and measured. The measured results are in good agreement with the simulated ones, and it shows that the fabricated SP4T switch achieves a bandwidth of 75 GHz-96 GHz, with an insertion loss and isolation about 4.8 dB and 28 dB, respectively. The fabricated switch also realizes a Pin1 dB about 22 dBm.

Radar cross section (RCS) reduction technology has great significance in stealth and other fields. A PSO-FSP algorithm is proposed based on the particle swarm optimization algorithm and the far-field scattering characteristics of coding metasurface to obtain the optimized coding sequence for RCS reduction. According to the principle of coding metamaterial, a 1 bit cell structure is designed. Therefore, a coding metasurface is constructed by arranging the unit cells based on the optimized coding sequence. Simulation results show that, in the case of vertical incidence, compared with metal plates of the same size, the metasurface can achieve more than 10 dB of RCS reduction within the broadband range from 15 GHz to 35 GHz, and the maximum reduction can reach 36 dB. The proposed coding metasurface has been successfully fabricated and measured, and there is a good agreement between simulated and measured results.

A novel ultra-wideband (UWB) printed monopole antenna with triple band-notched characteristics is proposed in this paper. The antenna bandwidth is extended by grooving on the connecting floor and increasing the impedance transformation line, with antenna bandwidth of 3.0~11 GHz and relative bandwidth of 114%. The overall antenna size is 35 × 30 mm². The complementary split-ring resonators (CSRRs) are loaded on the UWB antenna patch with microstrip wire feed. A symmetric J gap is loaded on the bottom plate, and the spiral gap is loaded on the feeder. The triple band-notched characteristics at 3.22~3.97 GHz, 4.94~5.84 GHz, and 7.25~7.86 GHz bands are realized. The gain of the designed antenna in the notch frequency segment can be reduced rapidly to -4 dbi, while the gain of other frequency bands is above 2 dBi. Simulated and measured results show that the antenna has stable gain and good radiation characteristics in the UWB frequency range.

This paper presents an exact analytical method to compute the air-gap magnetic field of surface-mounted permanent-magnet (SMPM) motors for evaluating slotting effects accurately. Solution field regions are divided into air-gap domain, permanent magnet (PM) domain, and slot domains. The Laplace's equations or Poisson's equations of the sub-domains are contacted by boundary conditions and then solved by exact analytical method. The actual height of slot and distance between slots are taken into account in the computation. Magnetic field distributions and cogging torque computed with the proposed analytical method are compared with those issued from 2-D finite-element method (FEM), and the comparison results are consistent and show the correctness and effectiveness of the proposed analytical method.

This paper presents the enhancement of bandwidth in circular and annular ring sectoral patch antennas. The cavity model approach has been used in identifying the higher order mode resonances that are close to each other in the sectoral patches. Bandwidth enhancement centered around these higher order mode resonances is achieved through the use of either a shorting pin or a parasitic patch. The sectoral patches have been simulated using ANSYS HFSS. The optimum position of the shorting pin and the dimension and position of the parasitic patch were determined through parametric simulations on HFSS. Measurements showed that the annular ring sectoral patch with optimally positioned shorting pin achieved 6.3 percent bandwidth with a return loss performance greater than 10 dB while the circular sector patch with a parasitic patch achieved 5.6 percent.

Electromagnetic scattering from time-varying sea surfaces under right-hand circularly polarized (RHCP) wave incidence is investigated, with emphasis on exploring the influence of nonlinear hydrodynamic interactions on Doppler spectral signatures as well as on examining the polarization difference of Doppler spectra between right-hand and left-hand polarized scattering waves. The choppy wave model (CWM) is adopted for describing nonlinear hydrodynamic interactions between ocean waves, and it is constructed by adding horizontal displacements through performing Hilbert transform for a reference linear surface model. Simulation results show that Doppler spectral signatures are significantly influenced by nonlinear hydrodynamic interactions in particular in low-grazing angle regime. It is also indicated that Doppler spectral signatures show distinct polarization dependence. In addition, numerical simulations show that Doppler shift of left-hand polarized scattering wave increases obviously with wind speed increasing, whereas the Doppler shift of right-hand polarized scattering wave looks less sensitive to wind speed variations. The result is potentially valuable in remote sensing applications with Global Navigation Satellite System-Reflectometry (GNSS-R) signals.