Array Elements Research Articles

A Deep Learning Approach for Beamforming and Contrast Enhancement of Ultrasound Images in Monostatic Synthetic Aperture Imaging: A Proof-of-Concept.

Goal: In this study, we demonstrate that a deep neural network (DNN) can be trained to reconstruct high-contrast images, resembling those produced by the multistatic Synthetic Aperture (SA) method using a 128-element array, leveraging pre-beamforming radiofrequency (RF) signals acquired through the monostatic SA approach. Methods: A U-net was trained using 27200 pairs of RF signals, simulated considering a monostatic SA architecture, with their corresponding delay-and-sum beamformed target images in a multistatic 128-element SA configuration. The contrast was assessed on 500 simulated test images of anechoic/hyperechoic targets. The DNN's performance in reconstructing experimental images of a phantom and different in vivo scenarios was tested too. Results: The DNN, compared to the simple monostatic SA approach used to acquire pre-beamforming signals, generated better-quality images with higher contrast and reduced noise/artifacts. Conclusions: The obtained results suggest the potential for the development of a single-channel setup, simultaneously providing good-quality images and reducing hardware complexity.

Performance Analysis of Multiple Interference Suppression of One Small Four Elements Array Antenna used in Satellite Navigation System

background: The anti-interference requirements of miniaturized satellite navigation arrays is increasing, the anti-interference ability reducing of small aperture arrays caused by large mutual coupling, large main lobe width, may be solved through adopting quad-arrays antenna. objective: Research of multiple interference suppression method is the aim of the paper, and it makes the research of small four element satellite navigation array antenna method: In the paper, it focuses on the structural design of low coupling polarized array antennas, and makes analysis of mutual coupling between array elements, the compensation technology based on auxiliary sources is proposed. result: Experimental analysis of antenna narrowband interference suppression are made. Relevant anti-interference results on four element antenna are also obtained. The anti-interference ability of four element antenna is summarized. conclusion: The anti-interference ability of four element antenna is analyzed and summarized in the paper, related results show that small four element satellite navigation array antenna can be used in the multiple interference suppression, in the satelliate navigation system.

COUPLED C-ESPRIT-BASED AZIMUTH AND ELEVATION ANGLE ESTIMATION WITH MINIMUM VARIANCE

This paper presents a method for conjugate estimation of azimuth and elevation angles based on the minimum variance C-ESPRIT method. The conjugate estimation method with minimum variance is a modification of the robust method based on the ESPRIT method with minimum variance and differs from it in that it does not require prior matching of signal duplicates. When modeling the signal acquisition from a unmanned aerial vehicle and processing it with the ESPRIT method, the data were distorted. Several signals were not displayed and noise appeared, which prevented the estimation of the signal arrival direction. The paper presents an efficient algorithm that can estimate the direction of arrival based on uncorrelated and one-dimensional signals. The method of conjugate estimation with minimum variance, when compared to the method of conjugate estimation without minimum variance, has been shown to improve the signal by a factor of 10. This improvement in signal quality allows one to conclude that the method is highly efficient. The C-ESPRIT-based minimum variance conjugate azimuth and location angle estimation method uses a robust minimum variance method with a conjugate rotation matrix to process a second subarray of data. An important aspect of the method is that it uses information from all array elements without grouping them and without computing the mean of the covariance matrices.

Double-sided visible moiré magnifier with hierarchical microstructure

Conventional moiré magnifier suffers from high manufacturing cost and poor scalability due to the stringent requirement on alignment between the microfocusing element array and micropattern array (MPA). By superposition of the microreflective element array and MPA together to form hierarchical microstructure, not only the alignment can be done during mold fabrication process, which is easily scalable and compatible to semiconductor, but also the synthetically magnified image is visible as viewed from both front and back side. The investigation of the moiré magnifier with hierarchical microstructure unveils new imaging phenomenon in moiré imaging device, and thereby offers a facile and low-cost platform to address challenges to open up a potential avenue in micro-optic involved three-dimensional display or anti-counterfeiting applications.

Fourier-Based Fast 3-D Ultrasound Imaging Using Row-Column-Addressed 2-D Arrays.

A Fourier-based fast 3-D ultrasound imaging method using row-column-addressed (RCA) 2-D arrays is presented. The row elements in an RCA array are activated sequentially, and all the column elements are used to receive. The obtained dataset is adapted to approximate to that obtained using a fully sampled array after a plane wave at a given incident angle is transmitted. In this way, the fast algorithm in plane-wave Fourier imaging (PWFI) can be applied to the adapted dataset. In addition, synthesizing multiple datasets based on multiple incident angles enables angular compounding, which improves the image quality. The proposed method was validated using computer simulations and physical-phantom experiments. The results show that the spatial resolution and contrast of the proposed method are comparable with those of its PWFI counterpart without requiring a fully sampled (FS) array. Compared with the delay-and-sum (DAS) method using the RCA array, the proposed method provides comparable spatial resolution but lower contrast; however, the computational complexity is significantly reduced from O(N4Nz) to O(WN2Nz log2(N2Nz)) , where N is the number of elements on each side of the RCA array, Nz is the number of voxels in the axial direction in the output image, and W is the number of compounding angles. For example, in the simulated results when the maximum compounding angle M is 5°, at a given point the lateral - 6-dB width provided by the proposed method is 0.241 mm (0.267 mm for DAS), the contrast ratio of a hyperechoic cyst is 8.87 dB (9.10 dB for DAS), the number of real number operations is reduced by a factor of 20.62, and the number of memory accesses is reduced by a factor of 47.21, both compared with DAS. This novel fast algorithm could facilitate the development of compact real-time 3-D imaging systems, especially when the channel count is high and a large field of view (FOV) is required.

Dielectric Lens Antenna for Industrial Radar Applications

Industrial radar applications like tank level measurement is an important research and application area in radar technology. Radar level measurement is a safe solution even under extreme process conditions (pressure, temperature) and vapors. Special antennas are required to meet electromagnetic requirements such as high gain, low sidelobe level and high bandwidth. The small side-beam level and narrow main beam primarily minimize reflections from the side of the tank, while the bandwidth determines the distance resolution of the measurement system. Another requirement is a small size and good manufacturability of the antenna. The main promising solutions are the use of microstrip, horn or dielectric lens antennas for tank level measurement systems. After several tests, we have concluded that the optimal choice for tank level radar measurement task, in terms of integrability and antenna parameters, is a dielectric antenna. The dielectric antenna has many other applications in modern mobile systems as 5 and 6 G systems where these antennas are elements of antenna arrays of beamforming or MIMO systems. In this paper, a special dielectric lens antenna is presented, satisfying main requirements, namely a circular antenna cross section, high antenna aperture efficiency and low sidelobe level. The center frequency of the antenna is 26 GHz with a band width of 1 GHz. The paper presents the analytic investigation and design of the dielectric lens antenna and the circular wave guide transition in detail. The electromagnetic design of the antenna was carried out using CST Microwave Studio 3D software.

Astrocyte Development in the Rodent.

Astrocytes have gained increasing recognition as key elements of a broad array of nervous system functions. These include essential roles in synapse formation and elimination, synaptic modulation, maintenance of the blood-brain barrier, energetic support, and neural repair after injury or disease of the nervous system. Nevertheless, our understanding of mechanisms underlying astrocyte development and maturation remains far behind that of neurons and oligodendrocytes. Early efforts to understand astrocyte development focused primarily on their specification from embryonic progenitors and the molecular mechanisms driving the switch from neuron to glial production. Considerably, less is known about postnatal stages of astrocyte development, the period during which they are predominantly generated and mature. Notably, this period is coincident with synapse formation and the emergence of nascent neural circuits. Thus, a greater understanding of astrocyte development is likely to shed new light on the formation and maturation of synapses and circuits. Here, we highlight key foundational principles of embryonic and postnatal astrocyte development, focusing largely on what is known from rodent studies.

УДОСКОНАЛЕНА МОДЕЛЬ ПАРАЛЕЛЬНОГО АЛГОРИТМУ СОРТУВАННЯ З ФОРМУВАННЯМ РАНГІВ

The model of parallel sorting of a number array with ranking based on the simultaneous application of high-speed decrement/increment operations according to the array of numbers and the array of their ranks is improved. Acceleration of the proposed algorithm is achieved by fixing the result of zeroing (n -1) elements of the number array instead of its complete zeroing. The description of the algorithm of parallel sorting with the formation of ranks in a compact form using the basis of Glushkov’s system of algorithmic algebras (SAA) is given. Keywords: system of algorithmic algebras, parallel sorting, mask, rank, decrement/increment.

Modulating photothermocapillary interactions for logic operations at the air-water interface.

We demonstrate a system for performing logical operations (OR, AND, and NOT gates) at the air-water interface based on Marangoni optical trapping and repulsion between photothermal particles. We identify a critical separation distance at which the trapped particle assemblies become unstable, providing insight into the potential for scaling to larger arrays of logic elements.

Visual rhetoric in advertising of China’s new tea beverage industry, using HEYTEA as an example

In recent years, China’s tea market has undergone immense transformations, giving rise to a diverse range of novel products collectively known as new tea beverages. This market trend has led to intense competition, compelling brands to employ innovative advertising strategies to captivate consumers. This study focuses on the well-known Chinese new tea beverage brand “HEYTEA” as a case study. It employs the theoretical framework of visual rhetoric to analyze visual rhetoric in new tea beverage advertisements from two dimensions: visual image and rhetorical techniques. In terms of visual image, advertisements effectively convey messages through a rich array of visual elements, attracting target audiences and enhancing their overall impact. On the other hand, within the domain of linguistic visual rhetoric, advertising copy emphasizes the use of words, sentence structures, and rhetorical devices to accentuate product features, thereby stimulating consumers’ sensory experiences. The objective of this research is to explore the value of visual rhetoric in new tea beverage advertising.

An Inquiry into the Concept of Tourism Attractiveness

The article delves into the intricate concept of tourist attractiveness, exploring the diverse array of elements that contribute to the attractiveness of a specific destination, place, or object for travelers. It comprehensively reviews existing methodologies for identifying and defining the constituent factors that shape overall tourist appeal, considering both broad perspectives and more nuanced categories such as destination attractiveness or allure of specific types of tourism. The outcome of this study is a meticulous examination of the components comprising tourism attractiveness, organized into distinct categories encompassing nature, culture and heritage, tourism infrastructure, sustainability, digitalization and broader tourism development, sports and entertainment, as well as hospitality and local communities.

High-Frequency Linear Array (20 MHz) Based on Lead-Free BCTZ Crystal.

Centimeter-sized BaTiO3-based crystals grown by top-seeded solution growth from the BaTiO3-CaTiO3-BaZrO3 system were used to process a high-frequency (HF) lead-free linear array. Piezoelectric plates with (110)pc cut within 1° accuracy were used to manufacture two 1-3 piezo-composites with thicknesses of 270 and [Formula: see text] for resonant frequencies in air of 10 and 30 MHz, respectively. The electromechanical characterization of the BCTZ crystal plates and the 10-MHz piezocomposite yielded the thickness coupling factors of 40% and 50%, respectively. We quantified the electromechanical performance of the second piezocomposite (30 MHz) according to the reduction in the pillar sizes during the fabrication process. The dimensions of the piezocomposite at 30 MHz were sufficient for a 128-element array with a 70- [Formula: see text] element pitch and a 1.5-mm elevation aperture. The transducer stack (backing, matching layers, lens, and electrical components) was tuned with the characteristics of the lead-free materials to deliver optimal bandwidth and sensitivity. The probe was connected to a real-time HF 128-channel echographic system for acoustic characterization (electroacoustic response and radiation pattern) and to acquire high-resolution in vivo images of human skin. The center frequency of the experimental probe was 20 MHz, and the fractional bandwidth at -6 dB was 41%. Skin images were compared against those obtained with a lead-based 20-MHz commercial imaging probe. Despite significant differences in sensitivity between elements, in vivo images obtained with a BCTZ-based probe convincingly demonstrated the potential of integrating this piezoelectric material in an imaging probe.

A low-profile antenna with parasitic elements and a DGS-based partial ground plane for 5G/WMAN applications

A low-profile antenna with three parasitic elements is designed and presented for fifth-generation (5G) and wireless metropolitan area network (WMAN) applications. This prototype covers the frequency range of 2.75–4.94 GHz, which is applicable for the lower 5G (3.33–4.2 GHz), WWAN n48 CBRS (US) (3.55–3.7 GHz), WiMAX rel 2 (3.4–3.6 GHz), n77 (3.3–4.2 GHz, most European and Asian countries), n78 (3.3–3.8 GHz, USA), and n79 (4.4–5.0 GHz, China, Hong Kong, Japan, and Russia) bands. The prototype is made of a low-loss, commercially available substrate material known as Rogers RT 5880 (εr = 2.2, tanδ = 0.0009) with a thickness of 0.79 mm. The optimized dimension of the proposed antenna is 35 × 25 × 0.79 mm3 (i.e., 691.25 mm3). The proposed 10-element array antenna is fed by a 50 Ω feeder. The maximum gain and directivity of the prototype antenna are 4.3 dB and 4.75 dBi, respectively. The radiation efficiency of the prototype varies from 86.79 to 92.14% (simulated) and from 86.23 to 91.48% (measured), and it is 89.48% (simulated) and 90.59% (measured) at 3.225 GHz. The impedance profile of the proposed 10-element array is (49.80-j1.72) Ω, which ensures good impedance matching. The VSWR and surface current of the low-profile antenna are 1.036 and 107.931 A/m at the center frequency of 3.225 GHz, respectively. The value of the scattering parameter (S11) is − 36 dB at the resonant frequency. By using a DGS-based partial ground plane and parasitic elements, it enhances bandwidth to 2.19 GHz. Therefore, the tested prototype is an excellent candidate to be deployed for 5G/WMAN applications with respect to the different presented parametric studies.

Self-similar ring element array develop for Fano response as mid-infrared: Liver cancer study

the mid-infrared metasurfaces play an important in optical applications including sensing and having Fano response is a benefit in this field for many goals including biosensing. So, these points are considered in this study and self-similar Plasmonic metasurface is suggested for sensing application. The suggested structure has a symmetrical formation but non-similar elements are considered to raise the Fano response. The structure contains five rings while the central one has a larger dimension than the four elements surrounding the central ring as an array of rings. The interaction of bright modes for both elements of the central ring and the array elements makes the Fano response at 1850 and 1910 nm while the single central ring has resonance at 1910 nm and the array rings have resonance at 1850 nm. The interaction of the element enhances the Q-factor of both resonances. The Full-wave method finite integrated technique (FIT) is used for modeling as a time domain method and the couple mother theory (CMT) is used for the analytical model. This metasurface is implemented as a sensor for detecting material under test and the sensitivity of the sensor is obtained 282 nm/RIU (Refractive Index Unit). Finally, the tissue of the liver as healthy and cancer cells are considered for examining the quality of the sensor.

Convex Optimization Algorithm for Maximizing Directivity of Conformal Array With DRR Constraint

The inconsistency of conformal array elements poses a huge challenge to pattern synthesis. Based on convex optimization theory, this paper proposes a novel directivity pattern synthesis method. It can maximize the directivity of dual‐polarized conformal arrays with a low dynamic range ratio (DRR). Firstly, the directivity function is presented under a dual‐polarized conformal array. Then the pattern synthesis based on maximizing directivity is summarized as a multiconstraint optimization problem. In addition, the DRR constraint is introduced to control the weight range. By using Taylor expansion, the problem is transformed into a convex optimization problem and solved iteratively. Finally, simulation results demonstrate that the proposed method can effectively achieve a good directivity pattern with low sidelobe level (SLL) and low DRR.

Intercoupling Suppression of Very Closely Spaced MIMO Antenna Based on Current Cancellation Method

Herein, a high isolation multiple-input–multiple-output (MIMO) antenna with a very close array element spacing, is proposed. By loading a pair of L-shaped parasitic stubs on the antenna feeder, the impedance matching bandwidth of the antenna is significantly improved. Furthermore, since the λ / 2 microstrip line can make the signal through it produce 180°phase transformation at the resonant frequency. A dielectric wall decoupling structure withλ / 2metal microstrip lines etched on both sides of the substrate is designed, and its profile height is 1.3 mm ( 0.022λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ).When the antenna element edge-to-edge distance is only 1mm ( 0.017λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ), the isolation of the MIMO antenna at the resonant frequency of 5.37 GHz is improved by 51.5 dB by introducing the dielectric wall decoupling structure. Finally, the close-spacing MIMO antennas using current cancellation method are compared, and the results show that the proposed decoupling structure is simple and has great versatility and extensibility.

Independent dual beams generated by array element division in integrated optical phased arrays

Independent dual beams generated by array element division in integrated optical phased arrays

FRACTAL GEOMETRY-BASED RESOURCE ALLOCATION FOR MIMO RADAR

The netted Collocated Multiple-Input Multiple-Output (C-MIMO) radar systems have attracted widespread attention due to their high resolution and excellent target detection capabilities. The self-similarity and spatial filling properties of fractal geometry enable antenna layouts to function effectively across multiple scales and frequency bands, which helps improve the overall performance and resource utilization of systems. In this paper, a radar array element model based on the Fudgeflake fractal is used to establish a target localization performance model directly related to power bandwidth allocation. Based on the model, a three-step solving strategy was designed with the Sequence Quadratic Program (SQP) algorithm as the foundation to achieve optimized allocation of power and bandwidth while maximizing overall performance. Experimental results demonstrate that under this algorithm, the use of power bandwidth resources is optimized through fractal geometry-based design.

Design of a Dual-Band Shared-Aperture Array Antenna Composed of Array Elements With High Electromagnetic Transparency

Design of a Dual-Band Shared-Aperture Array Antenna Composed of Array Elements With High Electromagnetic Transparency

An Energy-Efficient ECG Processor with Ultra-Low-Parameter Multi-Stage Neural Network and Optimized Power-of-Two Quantization.

This work presents an energy-efficient ECG processor designed for Cardiac Arrhythmia Classification. The processor integrates a pre-processing and neural network accelerator, achieved through algorithm-hardware co-design to optimize hardware resources. We propose a lightweight two-stage neural network architecture, where the first stage includes discrete wavelet transformation and an ultra-low-parameter multilayer perceptron (MLP) network, and the second stage utilizes group convolution and channel shuffle. Both stages leverage neural networks for hardware resource reuse and feature a reconfigurable processing element array and memory blocks adapted to the proposed two-stage structure to efficiently handle various convolution and MLP layers operations in the two-stage network. Additionally, an optimized power-of-two (OPOT) quantization technique is proposed to enhance accuracy in low-bit quantization, and a multiplier-less processing element structure tailored for the OPOT weight quantization is introduced. The ECG processor was implemented on a 65nm CMOS process technology with 4KB of SRAM memory, achieving an energy consumption per interference of 0.15 uJ with a power supply of 1V, 64% energy saving compared to the recent state-of-the-art work. Under 4-bit weight precision, the 5-class ECG signal classification accuracy reached 98.59% on the MIT-BIH arrhythmia dataset.