A miniaturized and closely packed eight element annular ring multiple-input multiple-output (MIMO) antenna array is designed to operate from 3 to 6 GHz band for 5G smartphone applications. In MIMO, the orthogonally placed antenna pairs maintain high isolation. The proposed decoupling structures placed between two adjacent antenna pairs improve the isolation. The decoupling structure consists of a rectangular metallic strip with metallic vias that reduces the mutual coupling and excites the additional modes to extend the bandwidth from 3 to 6 GHz. The MIMO structure offers isolation of more than 24 dB, ECC of less than 0.1, TARC of less than 7 dB over the complete operation band, DG of 10 dB, and more than 95% efficiency. The specific absorption rates (SARs) of the antenna placed in the human head and hand models are 0.41 W/Kg and 0.66 W/Kg, respectively. The performance obtained with the fabricated prototype offers excellent matching with that of the simulated ones.

The dual band notched features of an ultra-wideband (UWB) antenna are presented. The radiator element is a rectangular one with several slots. The planned antenna's operational frequency ranges from 2.8 to 10.6 GHz. By embedding a rectangular slot on the radiator and a folding stepped resonator in the ground plane, it is possible to create dual notched bands that are 3.76-5.9 GHz with a central frequency of 5.2 GHz (WLAN) and 2.85-3.32 GHz with a centre frequency of 3.2 GHz (WiMAX). The antenna measures 32 × 32 mm² across the board. In terms of VSWR, group delay, efficiency, and radiation pattern, the antenna's performance is confirmed. Results from simulation and testing of the stated antenna are closely matched.

A Mushroom-Cloud-shaped wide slot Microstrip patch antenna (MC-MSPA) was discovered and proved to be a viable option for Wideband applications in this research study. The given antenna has a high radiation and wideband reflection coefficient of 134.47% from 1.15 GigaHz to 5.87 GigaHz for |S₁₁|<-10 dB. This antenna has a peak gain of 6.47 dBi at 4.6 GigaHz and 6.1 dBi at 5 GigaHz, as well as an return loss of 47.37 dB at 1.88 GHz. MC-MSPA has optimised dimensions of 0.73λ_g×0.72λ_g×0.02λ_g. Furthermore, a reflecting surface of a 7×7 square-shaped array beneath the ground plane has been included to provide even higher gain and directivity. The proposed MC-MSPA+RP antenna has a fractional bandwidth of 63% with dual bands from 1.438 to 2.782 GigaHz and 38.89% from 3.964 to 5.878 GigaHz, with a peak gain of 9.657 dBi, maximum directivity of 10.44 dBi at 5 GigaHz, and maximum return loss of 54 dB at 4.9 GigaHz. Reflector plate electrical dimensions have been enhanced to 0.87λ_g×0.87λ_g×0.24λ_g. The proposed design improves gain and directivity, both of which are important for WLAN and Wi-MAX applications.

The exponential increase of data traffic in next generation wireless communication attracts optimized design of antenna arrays (AAs) to be deployed in RANs. The traditional antenna array synthesis techniques have become exhaustive leading to the introduction of machine learning assisted new binary optimization algorithm. In this paper, three specific AA features are given particular attention: peak sidelobe level (PSLL), first null beam width (FNBW), and broad sector null in interference directions. These contrast each other, and a multi-objective new binary cat swarm optimization (MO-NBCSO) with a novel mutation probability is developed to derive the best-compromised solutions among them. The computational complexity is approximated as O(MN²) (here, M and N represent the number of objectives and population size, respectively). Hence, a 20×20 planar antenna array is considered for synthesis and pareto fronts are generated alongside state-of-the-art MO algorithms. A fuzzy-based decision approach is introduced to choose the best trade-off solutions. A detailed comparative performance study is carried out by the two-performance metrics, namely, I-metric and S-metric. Numerical results illustrate that MO-NBCSO is a better candidate to produce the best antenna arrays in terms of array characteristics over other algorithms.

In this letter, a novel 3-D heterogeneous solenoid inductor with high inductance value is proposed. By adding planar spiral structure at the ends of through-silicon vias (TSVs) of typical 3-D solenoid inductor, the heterogeneous solenoid is formed. The total inductance is increased by more than 41% compared with that of typical solenoid inductor of the same size. Additionally, an accurate analytical model of the inductor is established considering all the factors including angle and offset. Q3D simulation results verified the accuracy of the model, and the percentage error is less than 5.38%. This work provides an important reference for inductor designers to quickly estimate inductance value, configuration, and layout area.

In this paper, we developed a hyperspectral transmission microscopic imaging (HTMI) system for rapid detection of pathogenic bacteria, which can realize precise identification and classification of mixed pathogenic bacteria to a single-bacterium level. The system worksin trans-illumination patterns and a self-developed dispersive hyperspectral imaging module is usedas the detection setup, providing spectral images with high SNR, and showing excellent performances with spatial resolution of 2.19 µm and spectral resolutions less than 1 nm. Hyperspectral microscopic imaging of five types of bacteria in low concentration were performed. The merging spatial-spectral profiles of individual bacteria for each species were extracted and utilized for species identification, achieving high classification accuracy of 93.6% using a simple PCA-SVM method. Species identification experiments of the mixed bacterial sampleswere further carried out, and the results demonstrate the validity and capability of the system assisted with simple machine learning methods to be used as an effective and rapid diagnostic tool for elaborate identification of mixed bacterial pathogen samples, providing guidance for the use of correct antibiotics.

In this paper, several multiband patch antennas with sinc-shaped edges were analyzed, designed, simulated and implemented for modern sub-6 GHz applications. The aim is to use the sinc function parameters such as amplitude and number of maxima (frequency) to control the antenna performance such as resonance and radiation characteristics. It is shown that changing the sinc pattern parameters has a significant impact on the resonance of the antenna, and hence these parameters can be used to directly control the multiband behavior of the antenna. The proposed antenna designs were manufactured, and their performance was tested experimentally in the lab and compared to simulation results. An acceptable agreement between experimental and simulated results was achieved.

The performance of the Vertical Cavity Surface Emitting Laser (VCSEL) for hybrid optical links SMF/FSO based on different data rates and MIMO configuration techniques was obtained using OptiSystem^TM which is close to the results of the experimental system. The developed system was tested with various transmission distances: 20, 30, 40, and 50 km, and in the existence of many configuration kinds and modulations. In addition to that the hybrid system was estimated with different weather cases: clear, rain, and snow. The results state that the performance of the OOK-NRZ system reveals better performance than OOK-RZ system under the same conditions. Also, the performance of the free space link is better than the fiber link formost of the link ranges considered and configurations. For OOK-NRZ of the fiber link, it was found that the MIMO 8×8 technique has better system performance than other configurations, and the Q-factor = 11.39 and BER = 5.4×10^-30 for a length of 50 Km while for the FSO link, it was found that MIMO 8×8 indicates a high performance for Q-factor = 12.7 and BER = 1.8×10^-37. The maximum FSO link distances under different weather conditions and coupling ratios were found. For BER≤10⁻⁹, in NRZ format for SMF 50 km utilizing MISO8×1 technology in clear weather for 10 Gbps, 15 Gbps, and 20 Gbps for FSO links, the maximum accessible lengths are 0.6 Km, 0.51 Km, and 0.43 Km, respectively. The process is expanded to include snow conditions for data rates of 10 Gbps, 15 Gbps, and 20 Gbps for FSO links with lengths of 0.4 Km, 0.3 Km, and 0.26 Km, respectively.

Methods of manual analysis for infrared image and temperature detection of power transmission and transformation equipment typically have problems, such as low efficiency, strong subjectivity, easy to make mistakes and poor real-time feedback. In this paper, a high temperature anomaly detection method based on SegFormer in infrared image of power transmission and transformation equipment is proposed. Many infrared images of power transmission and transformation equipment are collected and preprocessed, and the temperature information of each infrared image is read out using the DJI sdk tool to construct the temperature data matrix. In the segmentation stage, the SegFormer network is used to segment the key parts of the power transmission and transformation equipment to obtain the mask for detection. The maximum values of the temperature data in the mask area are calculated, and the high temperature anomaly detection atthe key parts of the power transmission and transformation equipment is realized. The test results on the test set show that the overall performance of the method is the highest as compared to other methods such as FCN, UNet, SegNet, DeepLabV3+, and an automatic temperature recognition can be realized, which has important practical value for the detection of high temperature anomaly at the key parts of power transmission and transformation equipment.

This paper designs a miniaturized, wide stopband microstrip filtering coupler based on coupled resonators. Firstly, a short-stub loaded uniform-impedance resonator (SSLUIR) is proposed, , and the size of the SSLUIR is reduced by adjusting the impedance ratio of the stubs and bending them. Then, the resonance performance of SSLUIR during electrical and magnetic coupling is studied. By adjusting the electrical length of the short stubs, higher harmonics are suppressed, and the upper stopband is widened. Finally, a 3 dB 180° microstrip filtering coupler is designed based on SSLUIRs. The measurement results show that the center frequency of the filtering coupler is 2.43 GHz, with a relative bandwidth of 6.6%. It can suppress harmonics within the 8.2f₀ range by more than 18 dB and has a size of 0.23λ_g×0.33λ_g. The correctness of the design method for miniaturized and wide stopband filtering coupler has been verified.

Plasmonic topological states, providing a new way to bypass the diffraction limits and against fabrication disorders, have attracted intense attention. In addition to the near-field coupling and band topology, the localized surface plasmonic resonance modes can be manipulated with far-field degrees of freedom (DoFs), such as polarization. However, changing the frequency of the topological edge states with different polarized incident waves remains a challenge, which has led to significant interest in multiplexed radiative topological devices. Here, we report the realization of polarization-wavelength locked plasmonic topological edge states on the Su-Schrieffer-Heeger (SSH) model. We theoretically and numerically show that such phenomenon is based on two mechanisms, i.e., the splitting in the spectra of plasmonic topological edge states with different intrinsic parity DoF and projecting the far-field polarizations to the parity of lattice modes. These results promise applications in robust optical emitters and multiplexed photonic devices.

This paper presents a novel design of Compact Notched Wide Band Antenna that has dual notches in the band of Wireless Local Area Network (5.15 GHz-5.825 GHz) and X-band Satellite Communication (8 GHz-12 GHz). The proposed antenna has a defective ground structure (DGS) to operate the antenna for wide band applications. Notch bands are achieved by inserting slots on the radiating patch and feed line. A horizontal S-shaped slot on patch is responsible for the notch in the band of wireless local area network, and an inverted U slot is used in feed line to get a notch in the band of Satellite Communication. The proposed antenna is fabricated using FR4 substrate of size 26 x 26 x 1.6 mm³ and tested using Vector Network Analyzer MS2037C. Although the measured results are slightly changed in comparison with simulated, they agree reasonably well. The measured result also reveals that the prototype antenna is in compact size and resonated from 4.24 GHz-12.59 GHz with two notch bands centered at 5.8 GHz and 10.3 GHz.

Wireless communication systems have developed significantly over the last few decades. Due to the saturation of lower frequencies of microwave spectrum (3-30 GHz) and the increasing need for high speed, emerging systems for consumer or professional use are progressively shifting to upper microwave and millimeter waves. Our study proposes a methodology for evaluating and classifying losses on a vertically polarized millimeter wave link at 80 GHz. To achieve this, we simulated the link budget of a Nokia 80UBT millimeter wave link operating in its real propagation space (with overground) with Pathloss 5.1 Design tool. Then we built a 3.58 km full-scale link in the Tongo-Bassa watershed of the coastal city of Douala in Cameroon. Analysing data collected over the period from December 06, 2020 to December 16, 2021 under Power BI allowed us to characterize the response of the millimeter signal in free space, during dry and rainy seasons. We then challenge ITU-R P.837-7 and ITU-R.P.838-3 Recommendations on statistical models of rainfall for propagation modeling, especially for millimeter signals propagated in an equatorial climate with heavy rainfalls. The study estimated a rainfall rate for 0.01% of the time at 110.1 mm/h, with a millimeter link cut-off for a rainfall rate greater than 64.8 mm/h, with a specific attenuation due to rain of 6.5 dB/km.

Linear Frequency Modulation (LFM) signals are widely used in radar and sonar technology. Many applications are interested in determining the source of an LFM signal. In recent years, the rapid development of machine learning has facilitated research in various fields, including signal recognition. The neural networks can extract the implicit features of the signals, which can help the system to sort and recognize the signal sources quickly and accurately. High performance of neural networks requires large amounts of high-quality labeled data. However, it is difficult and expensive to obtain a large amount of high-quality labeled data. Simultaneously, some features will be lost during data preprocessing, and feature extraction and classification tasks will be inefficient. The self supervised network is proposed in this paper for pre-training the signal waveform and fine-tuning the classification with a small amount of labeled data. The proposed method can extract more signal waveform features, save labeling costs, and has higher precision. This method can provide up to 99.7% recognition accuracy at 20 dB.

Generalized Mie theory provides a theoretical solution to the extinction cross-section curve of an electromagnetic scattering event with a multiparticle aggregate, given the configurational information of the constituent particles. However, deducing the configuration of the aggregate from the extinction cross-section curve is a non-trivial inverse problem that can be cast as a global optimization problem. To address this challenge, we propose a computational scheme that combines global optimization search algorithms with a calculator known as the Generalized Multiparticle Mie-solution The scheme is tested using mock scattering cross-section curves based on randomly generated aggregate configurations. The scheme successfully reproduces the scattering curve by minimizing the discrepancy between the two scattering curves. However, the ground-truth configuration is not reproduced, as initially expected. This is due to the inability of the global optimization algorithm scheme used in the present work to correctly locate the global minimum in the high-dimensional parameter space.Nonetheless, the partial success of the proposed scheme to reconstruct the mock curves provides an instructive experience for future attempts to solve the inverse electromagnetic scattering problem by fine-tuning the present approach.

In order to reduce the cogging torque and improve the back electromotive force (EMF) performance of the motor, a three-phase permanent magnet (PM) synchronous motor with magnetic pole eccentricity and slotting design is proposed in this paper. Firstly, the analytical expression for the cogging torque of the motor is derived based on the energy method, and the factors influencing cogging torque are analyzed. Subsequently, taking the cogging torque and the amplitude of the back EMF as the optimization objectives, the response surface method (RSM) and multi-objective genetic algorithm (MOGA) are combined to obtain the optimal values for the eccentricity distance of the PMs, slotting radius, and slot position. Finally, a finite element model is established for simulation comparison. The results show that compared with the traditional model, the optimized model effectively reduces the cogging torque while slightly sacrificing the back-EMF amplitude, and improves the sine degree of the no-load back-EMF.

This paper presents the design and implementation of a C-Band Frequency Generator developed for Space-borne Synthetic Aperture Radar. This Frequency Generator subsystem generates stable and coherent reference signals for all the sub-systems of C-Band Synthetic Aperture Radar payload. Frequency Generator based on frequency multiplication technique generates various coherent signals namely 500 MHz signal for digital clock, local oscillator (LO) signals of 900 MHz and 4500 MHz needed for receivers and chirp signal of 5400±37.5 MHz. This chirp signal is generated by direct modulation of the full bandwidth baseband signal of DC-37.5 MHz at 4500 MHz and subsequently mixing with 900 MHz signal. Frequency generator unit is realized in a compact two-tier architecture, using novel concept of full chirp modulation, resulting in 6° rmsphase error in the transmit chirp signal along with in-band spurious rejection better than 20 dBc, whereas other coherent frequencies resulting in out of band spurious rejection better than 53 dBc against the specification of 40 dBc.

The core structure of transformers and reactors is subject to stress and high-frequency excitation during operation. The core structure is made of laminated silicon steel sheets, which are subject to magnetostrictive strain under alternating magnetic fields. To investigate the comprehensive magnetic properties of oriented silicon steel sheets under the influence of harmonics and stress, this paper builds a magnetic property measurement system for electrical steel and investigates the magnetization and magnetostriction characteristics of oriented silicon steel sheets of type 30SQGD105 under working frequency, harmonic and applied stress conditions. The results show that the effects of harmonics and stress on the hysteresis characteristics of the silicon steel sheet are small, and the effects on the magnetostriction characteristics are large.

A metamaterial-inspired antenna is proposed that utilizes an artificial mu-negative (MNG) transmission line (TL) to incorporate the zeroth-order resonance (ZOR) into Wi-Fi 7 operation in the 2.4/5/6 GHz wireless local area network (WLAN) bands. The antenna comprises a meta-structured loop with periodically loaded series interdigital capacitors and a parasitic shorted strip, all formed on the same substrate layer in a coplanar structure. The 2.4 and 6 GHz bands are produced by the parasitic strip and the close-form loop strip, respectively, which are of typical right-handed antennas. The 5 GHz band caused by the ZOR mode, where the permeability is zero, can be adjusted by the series capacitance in the unit cell. The total antenna size is 5.4 mm × 19.6 mm only. In this work, the design applied to notebook computers for the upcoming Wi-Fi 7 operation is also demonstrated. Both numerical and experimental results validate our proof-of-concept design.

Pulmonary edema assessment is a key factor in monitoring and guiding the treatment of critically ill patients. To date, the methods available at the bedside to estimate the physiological correlation of pulmonary edema and extravascular pulmonary fluid are often unreliable or require invasive measurements. The aim of this article is to develop an imaging method of reliably assessing pulmonary edema by utilizing functional electrical impedance tomography. In this article, the Split-Bregman algorithm is used to solve the Total Variation (TV) minimization problem in EIT image reconstruction. A thorax model is constructed according to CT images of rats. Through simulation and experiment, the proposed method improves the quality of reconstructed image significantly compared with existing methods. A pulmonary edema experiment in rats is also carried out. The development of pulmonary edema is analyzed numerically through EIT images.