PIER C | PIER Journals

2024-04-20

PIER C

Vol. 142, 219-229, 2024

download: 115

Optical DC Transformers Incorporating Improved Sensing Cell Materials and Signal Processing

Jinfeng Luo

Optical direct current (DC) transformer has become a hot spot of research with its high accuracy, wide bandwidth, and high voltage isolation characteristics, but has the technical difficulties of low signal-to-noise ratio of ODCT signal and poor temperature stability. For this reason, the study proposes a new type of optical DC transformer integrating material science and signal processing. The study introduces an improved terbium gallium garnet crystal sensing unit material and a signal processing algorithm with a plus-window dual correlation detection algorithm, and constructs an optical DC transformer model. Simulation results show that the temperature compensation method can effectively weaken the influence of temperature change on the measurement accuracy under both warming and cooling conditions, and higher accuracy can be obtained by using the whole period window for measurement. The system applying terbium gallium garnet crystals helps to enhance the measuring system's output signal-to-noise ratio and sensitivity. Terbium gallium garnet crystals as a sensing material can further decrease the measuring error compared with other magneto-optical glasses. Taken together, DC measurement system using terbium gallium garnet crystals and dual correlation detecting algorithm can control the error to about 0.3 s. Simulation experiments verify the validity and feasibility of the research methodology, which can guide the research and application of optical DC transformers in the future.

Optical DC Transformers Incorporating Improved Sensing Cell Materials and Signal Processing

2024-04-16

PIER C

Vol. 142, 207-218, 2024

doi:10.2528/PIERC23091403

download: 198

Optimizable KNN and ANFIS Algorithms Development for Accurate Antenna Parameter Estimation

Rajendran Ramasamy and Maria Anto Bennet

The process of smart antenna synthesis involves the automatic selection of the optimal antenna type and geometry in order to enhance antenna performance. A model for intelligent antenna selection employs an optimizable K-nearest neighbors (KNN) classifier to determine the optimal antenna choice. To optimize the utilization of different learner types, the geometric parameters of the antenna are presented as the final step prior to the construction of the ANFIS model, which involves the integration of five distinct primary learners. The classification of three distinct types of antennas, namely helical antenna, pyramidal horn antenna, and rectangular patch antenna, is performed using an optimizable K-nearest neighbors (KNN) classifier. Additionally, an ANFIS approach is employed to determine the optimal size parameters for each antenna. The accuracy is used to evaluate the performance of an Optimizable KNN classifier, whereas Mean Squared Error and Mean Absolute Percentage Error are used to evaluate the performance of an ANFIS. The proposed technique demonstrates high performance in parameter prediction and antenna categorization, achieving a Mean Absolute Percentage Error of less than 3% and an accuracy exceeding 99.16%. The recommended methodology holds significant potential for widespread application in the development of practical smart antennas.

Optimizable KNN and ANFIS Algorithms Development for Accurate Antenna Parameter Estimation

2024-04-11

PIER C

Vol. 142, 195-206, 2024

doi:10.2528/PIERC24020305

download: 181

A Novel Multi-Objective Synchronous Optimal Subarray Partition Method for Transmitting Array in Microwave Wireless Power Transmission

Jianxiong Li and Chen Wang

To improve the beam collection efficiency (BCE) of the microwave wireless power transmission (MWPT) system while reducing the peak sidelobe level outside the receiving area (CSL) and system cost, this paper proposes a new subarray partition technique and a nonuniform sparsely distributed quadrant symmetric planar array (NSDQSPA) model. A particle swarm optimization algorithm based on multiple-objective with nonlinear time-variant inertia and learning factor improved particle swarm optimization (MO-NTVILF-IPSO) is also proposed. The one-step multi-objective subarray partition algorithm adopts dynamic weight and dynamic learning factor to carry out one-step optimization on the array element arrangement of the transmitting array. The optimization algorithm simultaneously optimizes two performance indicators: the ΔBCE, which represents the optimization accuracy for the BCE, and the α_ref, which represents the mean square error of the excitation amplitude before and after the subarray partition. Many simulation results show that the BCE is 94.91%, and the CSL is -13.41 dB when the transmitting array with an aperture of 4.5λ×4.5λ is divided into six subarrays. The simulation results further demonstrate that the proposed subarray division method is appropriate for the MWPT system and that the algorithm in this paper, when the array elements with the same excitation amplitude are divided for the planar transmitting array on the array model, and can guarantee relatively high BCE and relatively low complexity of the system feed network.

A Novel Multi-objective Synchronous Optimal Subarray Partition Method for Transmitting Array in Microwave Wireless Power Transmission

2024-04-09

PIER C

Vol. 142, 183-193, 2024

doi:10.2528/PIERC24010805

download: 213

Plug-and-Play ADMM Based Radar Range Profile Reconstruction Using Deep Priors

Kudret Akçapınar , Naime Özben Önhon , Özgür Gürbüz and Müjdat Çetin

Reconstructing a range profile from radar returns, which are both noisy and band-limited, presents a challenging and ill-posed inverse problem. Conventional reconstruction methods often involve employing matched filters in pulsed radars or performing a Fourier transform of the received signal in continuous wave radars. However, both of these approaches rely on specific models and model-based inversion techniques that may not fully leverage prior knowledge of the range profiles being reconstructed when such information is accessible. To incorporate prior distribution information of the range profile data into the reconstruction process, regularizers can be employed to encourage specific spatial patterns within the range profiles. Nevertheless, these regularizers often fall short in effectively capturing the intricate spatial correlations within the range profile data, or they may not readily allow for analytical minimization of the cost function. Recently, the Alternating Direction Method of Multipliers (ADMM) framework has emerged as a means to provide a way of decoupling the model inversion from the regularization of the priors, enabling the incorporation of any desired regularizer into the inversion process in a plug-and-play (PnP) fashion. In this paper, we implement the ADMM framework to address the radar range profile reconstruction problem where we propose to employ a Convolutional Neural Network (CNN) as a regularization method for enhancing the quality of the inversion process which usually suffers from the ill-posed nature of the problem. We demonstrate the efficacy of deep learning networks as a regularization method within the ADMM framework through our simulation results. We assess the performance of the ADMM framework employing CNN as a regularizer and conduct a comparative analysis against alternative methods under different measurement scenarios. Notably, among the methods under investigation, ADMM with CNN as a regularizer stands out as the most successful method for radar range profile reconstruction.

2024-04-07

PIER C

Vol. 142, 173-181, 2024

doi:10.2528/PIERC24012904

download: 114

Active Magnetic Bearing Three-Level Modulation Strategy Based on Mixed Logical Dynamical Model Prediction Controller

Yu Zou , Yongqiang Jiang , Fan Yang , Ye Yuan and Fuguang Wen

Active magnetic bearings feature advantages of frictionlessness, low loss, and high reliability, making them extensively utilized in fields such as flywheel energy storage, aerospace, and beyond. However, conventional modulation strategies applied to digital control systems suffer from control delays, reducing current control precision and resulting in increased current ripple. To address the aforementioned issues, firstly, the operating principle of the active magnetic bearing drive system is analyzed. Based on hybrid systems theory, a mix logical dynamic model of the drive system is established by introducing auxiliary logical variables and auxiliary continuous variables to achieve three-level modulation. Secondly, integrating model predictive control theory, the established model is utilized as a predictive model to forecast and compensate for control delays in controlling current. Finally, a cost function is established based on the error between predicted current and reference current, and optimal control signals are generated to achieve precise control of the active magnetic bearings. The simulation results demonstrate that under light load conditions, the modulation strategy proposed in this paper reduces current ripple by 49.94% compared to traditional modulation strategies. Under moderate load conditions, the proposed modulation strategy reduces current ripple by 49.96%, while under heavy load conditions, it reduces current ripple by 49.99%. This validates the effectiveness of the proposed modulation strategy in compensating for control delays while retaining the three-level modulation scheme.

Active Magnetic Bearing Three-level Modulation Strategy Based on Mixed Logical Dynamical Model Prediction Controller

2024-04-02

PIER C

Vol. 142, 161-171, 2024

doi:10.2528/PIERC24020901

download: 175

Fuzzy Dynamic Sequential Predictive Control of Outer Rotor Coreless Bearingless Permanent Magnet Synchronous Generator Based on Prediction Error Compensation

Shuai Zhuang , Gai Liu and Huangqiu Zhu

Outer rotor coreless bearingless permanent magnet synchronous generator is a complex and strongly coupled nonlinear system. The stable suspension and voltage of generator are always the focus and difficulty of research. The fuzzy dynamic sequential model predictive torque control method based on prediction error compensation is proposed. Firstly, the basic structure and working principle of the outer rotor coreless bearingless permanent magnet synchronous generator are introduced in this paper, and the mathematical model of voltage and suspension force is established. Secondly, the mathematical model is carried out to obtain the prediction equation, and the prediction error compensation is carried out to the prediction equation, and then the number of the first output voltage vectorsis determined by fuzzy controller. Finally, the designed control system is simulated and experimentally studied. The simulated and experimental results show that this control method can obtain good voltage and suspension response, and the outer rotor coreless bearingless permanent magnet synchronous generator has good dynamic performance and stability.

Fuzzy Dynamic Sequential Predictive Control of Outer Rotor Coreless Bearingless Permanent Magnet Synchronous Generator Based on Prediction Error Compensation

2024-04-01

PIER C

Vol. 142, 151-160, 2024

doi:10.2528/PIERC24022202

download: 201

Analysis of MIMO Channel Capacity for Terahertz Communication Systems

Abdelmounim Hmamou , Jamal Mestoui , Tanvir Islam , Mohammed El Ghzaoui , Narayanan Gangatharan and Sudipta Das

The primary focus of this paper is to evaluate the channel capacity of a Terahertz (THz) communication system using a Multiple Input Multiple Output (MIMO) technique. By deriving mathematical expressions for channel capacity and considering practical constraints, the paper provides insights into the performance of such systems under various conditions. The channel model used in this work accommodates the channel accuracies and transceivers constraints. To validate the proposed channel capacity, some simulations by taking into account deferent parameters namely SNR (Signal to Noise Ratio), MIMO channel Matrix size and distance between transmitter and receiver are performed. These simulations are carried out for 3 cases which are: (1) Channel State Information CSI is known to both transmitter (Tx) and receiver (Rx), (2) CSI is known to Rx but unknown to Tx, (3) CSI is unknown to both Tx and Rx. In this study, we introduce a mathematical formulation for a communication channel tailored for Terahertz (THz) applications. Using this channel model, we analyze the capacity of the THz channel. The suggested research has the potential to be applied in the design and enhancement of Terahertz (THz) wireless communication systems, aiding in the advancement of robust and high-capacity wireless networks that can fulfill the requirements of contemporary multimedia applications.

Analysis of MIMO Channel Capacity for Terahertz Communication Systems

2024-03-31

PIER C

Vol. 142, 143-150, 2024

doi:10.2528/PIERC24022001

download: 263

Design and Analysis of Printed Conformal Antenna System for Inter and Intra Vehicular (V2V) Communication Utilizations

Mudunuri Padmanabha Raju , Bathula Sadasiva Rao , Beulah Jackson , Tanvir Islam , Boddapati Taraka Phani Madhav , Sudipta Das and Yalavarthi Usha Devi

A multiple antenna placement system analysis for the improvement of efficiency and capacity for inter and intra vehicular communication is proposed in this article. Four antennas are placed in the four locations of the vehicular body which includes roof, side mirror, rear screen, and dashboard. The constituted antenna occu-pying the dimension of 40×38.5×0.2 mm³ on flexible substrate material of photo paper and the bending analysis of the model as per the conformal nature on vehicular body is also analyzed and presented in this work. The received power from each receiving antenna response with respect to the transmitter has been analyzed. The chan-nel capacity with respect to the antenna position for V2V communication is analyzed in different areas and in different environmental conditions.

Design and Analysis of Printed Conformal Antenna System for Inter and Intra Vehicular (V2V) Communication Utilizations

2024-03-30

PIER C

Vol. 142, 131-142, 2024

doi:10.2528/PIERC24020403

download: 162

Research on Resonant Wireless Energy Supply Circular Reactive Shielding for Small Electronic Equipment

Jishen Peng , Sylla Tidiani , Heyi Cao , Yuepeng Liu and Weihua Chen

A reactive power shielding structure working under 150 kHz for small electronic equipment was proposed to reduce the electromagnetic leakage of WPT system. First, the model of LCC-LCC compensation circuit was established. By ensuring transmission efficiency, a comprehensive analysis of nine sets of computational data results was conducted to select the scheme with the best shielding effect. The experimental results showed that the magnetic flux density attenuation was 27.82% at 41 mm transmission distance from the center under the optimal structure of 3 rings and 7 turns, inner diameter of 23 mm and outer diameter of 35 mm. The transmission efficiency can reach 76.73%, which is only 1.32% lower than the situation without shielding. The proposed reactive power shielding structure can significantly reduce the magnetic flux density in the external area of the WPT system without affecting the transmission efficiency of the system.

Research on Resonant Wireless Energy Supply Circular Reactive Shielding for Small Electronic Equipment

2024-03-26

PIER C

Vol. 142, 119-130, 2024

doi:10.2528/PIERC24012905

download: 240

A 4-Port Broadband High-Isolated MIMO Antenna for Wireless Communication

Ayyaz Ali , Maryam Rasool , Muhammad Zeeshan Zahid , Imran Rashid , Adil Masood Siddique , Moazzam Maqsood and Farooq Ahmad Bhatti

This article proposes a versatile Multiple Input Multiple Output (MIMO) antenna designed for contemporary wireless systems spanning frequencies from 3 to 20 GHz. It serves applications such as 5G mobile, WiFi, WiFi-6E, X-band, partial Ku, and K-band. The original single-element antenna evolves into a 4 × 4 MIMO configuration with optimized ground plane modifications for enhanced performance. A decoupling structure achieves over 20 dB isolation between inter-elements. The feeding structure, featuring a gradually changing design connected to the antenna's radiating structure, achieves wide bandwidth characteristics. This is further improved by a partial ground structure and slots on the radiating element. The lower frequency band of 3 to 7 GHz is attained with a rectangle-shaped radiator, while semi-circular microstrip lines atop the radiator enable the higher frequency bands of 8 to 15.4 and 18.7 to 20 GHz. The slots and ground structure enhance impedance bandwidth, and semicircles improve the radiation pattern. The MIMO antenna demonstrates measured peak gains of 4.4 dBi at 3.5 GHz, maintaining a radiation efficiency exceeding 80%. Validation through metrics like ECC, DG, CCL, and TARC confirms strong agreement between simulated and experimental results, positioning the MIMO antenna as a robust choice for various wireless communication applications.

A 4-port Broadband High-isolated MIMO Antenna for Wireless Communication

2024-03-20

PIER C

Vol. 142, 107-117, 2024

doi:10.2528/PIERC23122906

download: 205

Model Predictive Control with ESO and an Improved Speed Loop for PMSM

Dingdou Wen , Wenting Zhang , Zhongjian Tang , Xu Zhang and Zhun Cheng

An Improved Speed Loop (ISL) and Extended State Observer (ESO) strategy based on Model Predictive Control (MPC) of the Permanent Magnet Synchronous Motor (PMSM) is proposed in this paper. Firstly, considering the impact of load torque sudden changes on speed tracking performance, a reduced-order Luenberger observer is utilized to observe the load torque and combine with model prediction to form ISL. Secondly, the ESO is utilized to estimate the lumped disturbance and feedforward compensated to the improved speed loop, which improves the system's anti-interference performance. Then, a cost function that introduces the current tracking error at the switching point is constructed, reducing the current ripple. Finally, the experiments show that compared with the traditional PI speed control, the proposed strategy reduces the speed overshoot over a wide range of speeds, improves the speed tracking performance, and has superior dynamic performance and anti-disturbance performance under different operating conditions.

Model Predictive Control with ESO and an Improved Speed Loop for PMSM

2024-03-20

PIER C

Vol. 142, 95-106, 2024

doi:10.2528/PIERC24013101

download: 214

Compact Dual-Polarized Antenna with Wide Band and High Isolation Using Characteristic Mode Analysis

Zhongjie Zhan , Wen Huang , Rui Deng and Bao Li

In this paper, a compact dual-polarized antenna with wide band and high isolation is proposed, which can be applied to the 5G WiFi frequency band. The antenna is composed of 2 × 2 arrayed patches and two orthogonal L-shaped probe structures with reduced middle patch width and loaded U-shaped slots. The proposed antenna achieves a compact size by eliminating the need for a complex feeding network, instead utilizing only two closely spaced L-shaped probes for feeding. The antenna's radiation modes excited by two ports are orthogonal in polarization direction, and each port can excite two linearly polarized radiation modes respectively within the operating frequency band, thereby achieving dual-linear polarization and wideband performance. The antenna is analyzed and designed using characteristic mode analysis (CMA). By reducing the patch middle width and loading U-shaped slots on the L-shaped probe of the antenna, the suppression of high-order modes, improvement of isolation, and reduction of cross-polarization levels are achieved. The size of the antenna is 0.54λ₀ × 0.54λ₀ × 0.068λ₀ (λ₀ is the free-space wavelength of central frequency). The measured bandwidth is 23.5% (4.73 GHz-5.99 GHz) with |S₁₁| < -10 dB, |S₂₁| < -27.9 dB, boresight gain of 4.8 dBi-6.2 dBi and cross-polarization levels better than -23 dB.

Compact Dual-polarized Antenna with Wide Band and High Isolation Using Characteristic Mode Analysis

2024-03-19

PIER C

Vol. 142, 85-94, 2024

doi:10.2528/PIERC24012505

download: 228

A Wide Adaptation Variable Step-Size Adaline Neural Network Parameter Identification IPMSM Model Predictive Control Strategy

Qianghui Xiao , Xingwang Chen , Zhun Cheng , Zhongjian Tang and Zhi Yu

Model predictive control (MPC), as a frequently adopted control strategy for permanent magnet synchronous motors (PMSMs), exhibits favorable dynamic response capabilities. However, it necessitates an accurate mathematical model of the controlled object, and any parameter mismatch can lead to a decline in control performance. This paper proposes a model predictive current control (MPCC) method based on parameter identification, which can be extended to the parameter identification of plug-in permanent magnet synchronous motors (IPMSMs). A wide-adaptability variable step-size algorithm is designed in response to the varying effects of single variable step-size functions on parameter convergence speed and ripple when the motor experiences different parameter disturbances. This method classifies and fits various variable step-size functions based on the maximum value of the absolute value of different instantaneous errors. This allows different variable step-size functions to adapt to different parameter disturbances, resulting in rapid waveform convergence and consistent ripple size in the identification process. Additionally, a new variable step-size function type was designed with simple parameter settings and easy debugging. Finally, the effectiveness of the proposed method was verified through experiments, and the results showed that the method can achieve fast and accurate identification of multiple parameters under different parameter perturbations, ensuring stable current control.

A Wide Adaptation Variable Step-size Adaline Neural Network Parameter Identification IPMSM Model Predictive Control Strategy

2024-03-18

PIER C

Vol. 142, 75-83, 2024

doi:10.2528/PIERC23122904

download: 169

Optimization of Electromagnetic Thrust for Short Primary Unilateral Linear Induction Motor

Cheng Wen , Junyi Chen , Jian Cui , Zhiping Wan and Yujian Chang

In this paper, four different structures are proposed to optimize electromagnetic thrust for the primary and secondary pole linear induction motors. Firstly, the two-dimensional topology structure of the motor is established, and the correlation equation of electromagnetic thrust is established. Secondly, the electromagnetic thrust optimization of the primary structure of the motor is carried out by the chamfer method and trapezoidal structure method. Then, the secondary structure of the motor is slotted and mixed with different conductivity materials to optimize the electromagnetic thrust. At the same time, a motor model with high permeability under ideal conditions is proposed from the angle of relative permeability of secondary aluminum plate. Finally, the four optimized structures were simulated, and the changes of electromagnetic thrust, air gap density, and back electromotive force were analyzed. The simulation results fully verify the effectiveness of the four optimization structures proposed in this paper.

Optimization of Electromagnetic Thrust for Short Primary Unilateral Linear Induction Motor

2024-03-15

PIER C

Vol. 142, 61-73, 2024

doi:10.2528/PIERC24012803

download: 280

Microstrip Patch Antenna with Multi-Fins for Radio Frequency Energy Harvesting Applications

Mohammed Muataz Hasan and Ahmed M. A. Sabaawi

A novel multiband microstrip patch antenna (Antenna-1) is introduced in this paper to target the frequencies of interest required for RF energy harvesting applications, including mobile DCS (Digital Cellular System), mobile LTE (Long Term Evolution), mobile 5G, WLAN (Wireless Local Area Network), and WIMAX (Worldwide Interoperability for Microwave Access) services. The simulated results for the proposed antenna showed outstanding performance. The antenna supports a high number of total (11) eleven operating frequencies and covers all of the frequencies of the 2.4 GHz (IEEE 802.11) band, as well as the downlink frequencies of mobile DCS 1800 and the downlink frequencies for mobile LTE/5G (Band 68). The proposed antenna has achieved a high gain for most of its resonating frequencies, with a high gain of (4.49 dBi) at the frequency of (2.4527 GHz), and a peak gain of (6.349 dBi) at the frequency of (3.95 GHz). Furthermore, the proposed antenna achieved a high bandwidth capacity of (677 MHz) at the resonating frequency of (5.2 GHz), which covers a lot of frequencies utilized by WLAN, WIMAX, and mobile LTE services, making it a suitable antenna for radio frequency energy harvesting applications. Good agreement between the measured and simulation results was observed.

Microstrip Patch Antenna with Multi-fins for Radio Frequency Energy Harvesting Applications

2024-03-12

PIER C

Vol. 142, 51-60, 2024

doi:10.2528/PIERC24010501

download: 230

Multi-Objective Optimization of a Multi-Tooth Flux-Switching Permanent Magnet Machine with HTS Bulks

Huajun Ran , Yunpan Liu , Linfeng Wu and Junye Zhao

Flux-switching permanent magnet (FSPM) machine has wide application prospects in aerospace and automotive fields. To enhance the machine's electromagnetic performance, a novel multi-tooth flux-switching permanent magnet (MT-FSPM) machine with high-temperature superconducting (HTS) bulks is proposed. The HTS bulks are arranged in the middle of the stator teeth, aimed at diminishing flux leakage and amplifying torque output. The method of stator tooth chamfering and rotor flange is adopted to effectively suppress the torque ripple. Then based on the comprehensive sensitivity analysis, the key design parameters of the machine are layered, and the high sensitivity parameters are optimized by response surface method (RSM) and multi-objective genetic algorithm (MOGA) to obtain the optimal value. Finally, a 6/19 MT-FSPM machine model is established in 2D finite element method (FEM). Comparative analysis with the conventional model indicates a 16.4% increase in output torque and an impressive 79.6% reduction in torque ripple for the proposed model.

Multi-objective Optimization of a Multi-tooth Flux-switching Permanent Magnet Machine with HTS Bulks

2024-03-08

PIER C

Vol. 142, 37-49, 2024

doi:10.2528/PIERC24012501

download: 201

Current Sensor Fault Detection and Fault-Tolerant Control of Bearingless Induction Motor Based on VCS

Shihan Zhan , Zebin Yang , Xiaodong Sun and Qifeng Ding

To ensure normal operation of a control system for a bearingless induction motor (BIM) after current sensor failure, a virtual current sensor (VCS) fault-tolerant control strategy was proposed. First, on the basis of the coordinate transformation of the stator current of the torque winding, the fault detection marks were set to realize current sensor fault detection. Second, according to the mathematical models of BIM, the stator current differential equations included in the VCS were derived, and the solutions of the equations were used as the reconstruction current of the fault current sensor, achieving fault-tolerant operation control after the sensor fault. The simulated and experimental results show that the set fault detection marks can realize the quick and accurate identification of sensor faults, and the estimated current from the VCS output can replace the faulty current after the current sensor fails, and the stator current can be reconstructed effectively under no-load, load change, and speed change conditions, and also ensure a good suspension of the motor rotor under sudden addition of disturbance condition.

Current Sensor Fault Detection and Fault-tolerant Control of Bearingless Induction Motor Based on VCS

2024-03-06

PIER C

Vol. 142, 27-35, 2024

doi:10.2528/PIERC23101706

download: 189

Harnessing Polarization Diversity for Enhanced Reliability in Free Space Optical Communications

Amar Tou , Samia Driz , Benattou Fassi and Ikram Sabrine Khelifa Mahadjoubi

This article delves into the strategic application of polarization diversity in Free-Space Optical (FSO) communication systems. With the overarching aim of optimizing data transmission and bolstering reliability, the paper explores the utilization of diverse polarization orientations to navigate the challenges posed by varying atmospheric conditions. By transmitting identical data streams through different polarization states, the impact of atmospheric turbulence is effectively mitigated, leading to enhanced signal quality and system dependability. This article sheds light on the theoretical underpinnings and simulation modeling of harnessing polarization diversity in FSO communication. The simulations conducted in this study using OptiSystem software ver. 17 demonstrate the effectiveness of this approach in mitigating the adverse impacts of atmospheric turbulence. Notably, the results consistently indicate that the integration of polarization diversity leads to lower Bit Error Rates (BER) across a spectrum of turbulence conditions. Furthermore, the proposed FSO system exhibits a remarkable ability to sustain robust communication capabilities over extended distances, outperforming the conventional system. Significantly, the proposed FSO system under weak, moderate and strong turbulence conditions achieves operational distances of approximately 4250, 3750 and 3200 meters, respectively compared to conventional system, which achieves distances of 3750, 3250 and 2250 meters, respectively. This significant performance disparity underscores the potency of the proposed FSO system in overcoming the challenges of atmospheric turbulence and extending the reach of optical communication.

Harnessing Polarization Diversity for Enhanced Reliability in Free Space Optical Communications

2024-03-02

PIER C

Vol. 142, 13-25, 2024

doi:10.2528/PIERC24010302

download: 237

Research on Circular Polarization Composite Scattering Characteristics of Sea Surface and Ship Target at GPS Frequency

Ye Zhao , Long-Wen Liao , Ya-Jie Liu , Wei Tian , Xincheng Ren and Peng-Ju Yang

The electromagnetic characteristics analysis of the scattering signals from targets, which usually exist or are hidden in the surrounding environment, is one of the necessary prerequisites for the reliable reception of echo signals. Utilizing the GNSS signals as an opportunistic illumination source for detecting maritime targets has vast development prospect and scientific application value. GNSS signals, including GPS signals, are the right-hand circular polarization waves at L-band. Therefore, in this study, a comprehensive electromagnetic composite scattering model is established under circular polarization, which encompasses sea surface scattering, target single scattering, target multiple scattering, and coupled scattering between the target and sea surface. Then, the research investigates the variation characteristics of different scattering components (including the scattering of sea surface, the first, second, and third-order scattering of target, the total scattering of target, the coupled scattering of target induced by the reflection waves from sea surface, and the coupled scattering of sea surface induced by the reflection waves from target) in the composite scene under different polarizations, incident angles, wind speeds, and headings. The results indicate that the scattering of sea surface under LR polarization (which means that the polarization states of scattering and incident wave are left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP), respectively) is significantly greater than that under RR polarization, while the opposite trend is observed for the target. Therefore, in the applications such as the detection and identification of ship targets on sea surface, it is better to choose the right-hand circular polarization channel to receive the scattering echo signal from target, which could effectively suppress the scattering echo of sea surface. These findings are of crucial significance in enhancing the effectiveness and accuracy of maritime target detection.

Research on Circular Polarization Composite Scattering Characteristics of Sea Surface and Ship Target at GPS Frequency

2024-02-29

PIER C

Vol. 142, 1-11, 2024

doi:10.2528/PIERC24010101

download: 293

High Gain Compact Dual Band Antenna Using Frequency Selective Surface for 5G and WLAN Applications

Shubhangi Mangesh Verulkar , Anjali Rochkari , Mahadu Annarao Trimukhe , Varsha Bodade and Rajiv Kumar Gupta

In this paper, a high gain antenna using Frequency selective Surface (FSS) is proposed. The compact structure is designed from a circular Ultra-wide band (UWB) monopole. Higher order modes of UWB antenna are suppressed by decreasing the thickness of the monopole, ground plane dimensions and increasing the gap between the ground plane and the monopole. Symmetrical portion of circular monopole is etched to form a semicircular monopole, and an off-set feed is employed. Dual band characteristics and miniaturization are achieved by etching horizontal and vertical slots and reducing ground plane dimensions. An FSS reflector is designed for gain enhancement. This miniaturized antenna offers less blockage and therefore, higher gain improvement when an FSS is used as a reflector.