In this research work, a flexible metamaterial inspired antenna is proposed. The substrate is made of polyamide making it bendable. The stepwise detail analysis is discussed, and the antenna has two complimentary split resonators with circular ring placed in the ground plane. A superstrate along with an EBG structure is added in the final design. Mathematical modelling is done to prove metamaterial structure. To test the on-body results, first the permittivity of different fabrics is measured using DSL-01 (SES Instruments Pvt. Ltd). Phantom solution is required to test In-Body (Implantable) results.

In order to improve the distance of 5th Generation (5G) Mobile Communication Technology) millimeter-wave outdoor point-to-point relay transmission, a 2-port Multiple Input Multiple Output (MIMO) antenna with high gain and low sidelobe level characteristics is designed at 39 GHz. The antenna is designed using the Taylor synthesis method and slotting technology to increase the antenna gain and lower the sidelobe level. Loading hollow T-shaped branches reduces the mutual coupling between MIMO antennas. The measured results are basically in line with the simulation ones. The results show that the bandwidth of the antenna is 38.1 ~ 39.3 GHz; the isolation degree is more than 50 dB; the antenna gain is 25.75 dBi at 39 GHz; the E-plane and H-plane sidelobe levels are -20.5 dB and -20 dB, respectively. Furthermore, the Envelope Correlation Coefficient (ECC) is less than 0.022; the Diversity Gain (DG) is more than 9.89; and the radiation efficiency reaches 90% in the working frequency band. Therefore, this antenna can be used as a long-distance relay antenna in 5G millimeter-wave communication system with high gain and low sidelobe level characteristics based on meeting the requirements of the MIMO antenna.

Phase noise is a common hardware impairment that affects the performance of beamforming systems. Therefore, analysis of its impact is of great practical interest. Although Sidelobe Cancellation (SLC) is a mature technique, existing analyses typically ignore the effect of phase noise, due to the shared assumption that the down-conversion circuits have a common local-oscillator (LO). However, when distributed phase-lock-loops (PLLs) are used, the impact of phase noise cannot be neglected. Therefore, this paper derives new mathematical models of performances, including signal-to-interference-plus-noise ratio (SINR) and beamforming gain. Exact and approximated analytical models are obtained, respectively. In addition, we propose an average beam pattern formula to replace the traditional beam pattern formula, to improve the consistency between beam null depth and the beamforming gain. The theoretical findings are verified through signal-level simulations.

In the traditional Direct Instantaneous Torque Control (DITC) strategy for permanent magnet assisted switched reluctance motors, the hysteresis control mode during the commutation phase and the single-phase on-period is not smooth, resulting in excessive synthetic torque ripple. In this paper, we analyzed this problem, combined with the principle of hysteresis segmentation control and pulse width modulation (PWM), and proposed a hysteresis segmented PWM-DITC strategy. By analyzing the torque error changes in each division area of the inductor, the torque error is adjusted by the internal hysteresis loop during the commutation period and the single-phase on-period, so that the hysteresis control is smoother, and the torque ripple is reduced. At the same time, the linear model of rotor angle and inductance is established; the PWM voltage modulation calculation formula at both ends of the winding is calculated and derived; the hysteresis output signal at the commutation time and the single-phase on-time is optimized to further suppress the torque ripple. Finally, through simulation and experimental demonstration, the proposed hysteresis loop segmented PWM-DITC strategy can overcome the problem of unsmooth hysteresis control mode and can effectively suppress torque ripple.

In recent years, Radio Frequency Energy Harvesting (RFEH) has matured into a trustworthy and consistent method of obtaining ambient energy. For this energy to be utilized, it must be collected as efficiently over a broad range of frequencies as possible. In this regard, this article introduces a quad-band low-power, highly sensitive Radio Frequency (RF) to Direct Current (DC) signal converter circuit that operates at 1.5 GHz, 2.45 GHz, 3.6 GHz, and 5.5 GHz bands. The converter circuit is realized through single and dual-band converter circuit studies. These circuits comprise an impedance matching circuit, a voltage-doubler rectifier, a DC-pass filter with a resistive load of 5 kΩ, and a DC-DC voltage booster (LTC3108). The proposed quad-band converter circuit without a voltage booster gives a DC output voltage of 118 mV, 81 mV, 56 mV, and 24 mV at the four operational frequencies on a low input power of -25 dBm, respectively. A DC voltage of 3.3 V is obtained when the converter circuit is connected to a voltage booster. Maximum conversion efficiency achieved is 48% from four tones on a power input of -10 dBm. Circuit design steps, matching conditions, and performance parameters are presented using the Advanced Design System (ADS) and LTspice simulation tools.

In this paper, a compact Ultra Wide Band (UWB) Multiple Input Multiple Output (MIMO) antenna using circular slots Electromagnetic Band Gap (EBG) structures operating in frequency band from 3.1 GHz to 10.6 GHz is presented. The size of this compact antenna is 26 × 33 mm². In wireless communications, such as WLAN, 4G, and 5G, MIMO has become an essential element. However, the major limiting factor of MIMO systems is mutual coupling due to the smaller spacing between multiple antennas, which reduces spatial diversity, antenna gain and can also result in unwanted interference and cross-talk between antenna elements. To enhance antenna performance and reduce the mutual coupling, EBG structures are used. Incorporation of EBG structures in MIMO antenna eliminates surface wave propagation, which reduces the mutual coupling. In this work, the design of a dot notch shaped UWB-MIMO antenna with a circular slot EBG structure is proposed. Results presented here are simulated by using CST microwave software studio. From the results it can be observed that the proposed antenna has bandwidth of 3.1 GHz-10.6 GHz. It exhibits 6.72 dB peak gain and reduces the mutual coupling considerably, i.e., more than -28 dB.

In this paper, equivalent circuit models are first presented for characterizing the CPW SSPPs with etched slot. The asymptotic frequency and dispersion are investigated based on the theoretical model. And the analyses reveal that both the asymptotic frequency and dispersion curve can be manipulated by changing the inductance brought by the etched slots and the capacitance of the loaded capacitors. To validate the propagation performance, the proposed SSPP structure was fabricated and tested. The experimental results are consistent with the theoretical analysis, indicating that the designed SSPP structure possesses excellent low-pass filtering characteristics. Compared with traditional SSPP structures, the proposed structure exhibits a much narrower transversal width and does not require mode-conversion structures.

This article introduces a planar monopole antenna specially designed for NB-IoT module devices. The preferred choice for Internet of Things (IoT) technology is the Narrow-Band Internet of Things (NB-IoT) due to its extensive coverage and low power consumption. NB-IoT is specifically designed for IoT applications. A circular patch antenna with dimensions of 30 mm×60 mm is fabricated, which is specifically tailored for the NB-IoT module. The antenna dimensions are meticulously chosen to ensure compatibility with the device module, considering the NB-IoT B1 (2100) and B3 (1800) frequency bands. Among various patch shapes, the circular design is preferred for its advantages over hexagon and square patches. The desired antenna configuration combines a square-slotted patch with a monopole ground plane, and it offers several advantages in terms of design simplicity, compact size, and characteristics such as broad bandwidth, acceptable gain, and high radiation efficiency. The design process employs HFSS Software and utilizes an FR4 substrate of 1.6 mm thickness. Operating at resonance frequencies of 2.1 GHz and 1.8 GHz, the antenna covers a broad frequency spectrum of 1100 MHz (1.5 to 2.6 GHz) with a fractional bandwidth of 53.65%. The suggested antenna achieves a peak gain of 3.3 dB and maximum radiation efficiency of 96% within its operating band. It exhibits an omnidirectional radiation pattern, meeting the specific requirements of NB-IoT technologies. Experimental measurements of the fabricated antenna validate the results achieved from the simulated data.

This research article introduces a compact wearable antenna designed specifically for medical applications. The antenna underwent prototyping using a flexible Rogers Duroid RO3003^TM material, featuring a small form factor measuring 35 × 32 × 0.5 mm³. In the initial phase of the design process, a basic P-shaped rectangular patch antenna was employed. However, during the first design iteration (Design 1), the antenna demonstrated a single resonance around 1.2 GHz, although it was not optimally matched at that frequency. To tackle this problem and achieve miniaturization involved the introduction of two rectangular patches positioned below the P-shaped patch known as Design 2. To further improve its performance, an inverted L-slot was incorporated. The frequency of operation for the antenna is 2.4 GHz, with a bandwidth measuring 25.2% ranging from (2.087-2.692) GHz. The measured radiation patterns demonstrate bidirectional properties in the E-plane and omnidirectional properties in the H-plane and maintain a high gain of 3.54 dBi and an efficiency of 91%. The SAR values are 0.018/0.013 Watt/kg on the chest. Similarly, the SAR values are 0.02/0.015 Watt/kg on the thigh, using 1/10 g of human tissue, which comply with the standards set by the FCC and the ICNIRP. Furthermore, the simulation and measurement under bending investigation and being close to the human body demonstrate excellent performance. Therefore, the suggested antenna holds significant potential as a compact solution for wearable medical applications.

Micro Deformation Monitoring Radar has been widely used in the field of surface deformation and displacement monitoring. However, limited by radar imaging geometry, the deformation measurement by existing radar technology can only extract the deformation and displacement of the target line of sight (LoS), which cannot directly reflect the actual deformation and displacement of the landslide direction and easily results in misjudgment or omission of the surface deformation monitoring information. In this paper, the relationship model and mapping between radar data and three-dimensional coordinate system were analyzed to perform three-dimensional analysis of the LoS displacement. Combined with the landslide displacement direction, the mapping angle between the LoS direction at any point in the observation area and the landslide direction was solved, and then the deformation displacement in the landslide direction was obtained by solving the LoS direction displacement. Finally, taking the measured data of one slope as the research object, the feasibility and accuracy of the method were analyzed and verified. The conclusion shows that the method proposed in this paper can be effectively applied to calculate the true value of landslide deformation.

Utilizing deep learning to replace numerical simulation solvers for electromagnetic wave propagation is a promising approach for the rapid design of photonic devices. However, to realize the advantages of deep learning for rapid design, it is essential to apply it to a general device structure. In this study, we propose a method that employs deep learning to assist in fast design of a general grating coupler structure. We use a modified 1D-ResNet18(1D-MR18) to predict the coupling efficiency of various grating couplers at different wavelengths. After comparing and selecting the optimal combination of learning rate, activation functions, and batch normalization size, the 1D-MR18 demonstrates remarkable accuracy (MSE: 2.18×10^-5, R²: 0.969, MAE: 0.003). By integrating the 1D-MR18 with the adaptive particle swarm algorithm, we can efficiently design periodic and nonuniform grating couplers that meet various functional requirements, including single-wavelength grating couplers, multi-wavelength grating couplers, and robust grating couplers. The time for designing a single device is no more than 2 minutes, and the shortest is only 17 seconds. This novel approach of employing deep learning for the fast and efficient design from standard photonic device structures offers valuable insights and guidance for photonic devices design.

In this work, a novel time domain Transmission Line Matrix (TLM) algorithm with Symmetrical Condensed Node (SCN) is developed to model electromagnetic (EM) wave propagation through a single graphene layer in Terahertz (THz) spectrum. The intraband conductivity of graphene (assumed to follow the Drude model) is implemented in TLM method by using the Auxiliary Differential Equation (ADE) of conduction current density. The validity and stability of the obtained results demonstrates the effectiveness and precision of this new modeling technique named ADE-(SCN)TLM, and prove that this method is a powerful tool that can be used to model and simulate complex devices based on graphene sheet for terahertz applications (e.g., Electronics, optoelectronic, ect.).

The linear sampling method (LSM) is a qualitative inverse scattering technique for reconstructing the shape of a target. It has several beneficial qualities, including the avoidance of nonlinear optimization and simplified scattering approximations. However, it often struggles when sensors can only be placed on one side of the target. In this paper, we investigate two alternative LSM formulations for overcoming the limited-aspect challenge. The first, the phase-delay frequency variation LSM (PDFV-LSM), incorporates coherent processing across frequency to improve discrimination in the range direction. The second, the phase-encoded LSM (PE-LSM), enhances the PDFV-LSM approach with a receive-beamforming operation to decrease the complexity of the inverse problem. We apply both techniques to simulated data from three-dimensional targets and three-dimensional limited-aspect arrays. We generate three-dimensional reconstructions and compare them to reconstructions from both the conventional LSM and conventional backprojection-based processing. The results demonstrate superior reconstruction fidelity for either the PDFV-LSM, the PE-LSM, or both, across a wide variety of imaging scenarios due to finer range resolution. They also demonstrate trade-offs between the two enhanced LSM techniques, with the PE-LSM achieving better range resolution and robustness to noise and the PDFV-LSM achieving better lateral resolution.

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.