scholarly journals MLFMM techniques for efficient analysis of random array configuration for SKA radio telescope

2017 ◽  
Vol 2017 (12) ◽  
pp. 656-658
Author(s):  
Shantanu K. Padhi
Keyword(s):  
Radio Telescope ◽  
Array Configuration ◽  
Random Array

scholarly journals Design of 2D Sparse Array Transducers for Anomaly Detection in Medical Phantoms

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5370
Author(s):  
Xiaotong Li ◽  
Anthony Gachagan ◽  
Paul Murray
Keyword(s):  
Fibre Composite ◽  
Evaluation Criteria ◽  
Array Configuration ◽  
Array Pattern ◽  
Array Transducer ◽  
Random Array ◽  
Spiral Array ◽  
Imaging Performance ◽  
Tissue Mimicking Material ◽  
Tube Structure

Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower array, have been considered for their potential as conformable transducers able to image within a focal range of 30–80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions. Two evaluation criteria, peak sidelobe level (PSL) and integrated sidelobe ratio (ISLR), are used to access the performance of each array configuration. Subsequently, a log spiral array pattern with −19.33 dB PSL and 2.71 dB ISLR has been selected as the overall optimal design. Two prototype transducers with the selected log spiral array pattern have been fabricated and characterised, one using a fibre composite element composite array transducer (CECAT) structure, the other using a conventional 1–3 composite (C1–3) structure. The CECAT device demonstrates improved coupling coefficient (0.64 to 0.59), reduced mechanical cross-talk between neighbouring array elements (by 10 dB) and improved operational bandwidth (by 16.5%), while the C1–3 device performs better in terms of sensitivity (~50%). Image processing algorithms, such as Hough transform and morphological opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios, including bespoke phantoms using tissue mimicking material. Experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm.

Effect of feed array configuration on the Field-of-View of radio telescope antenna

2013 ◽  
Vol 30 (4) ◽  
pp. 362-367 ◽  
Author(s):  
Yang Wu ◽  
Biao Du ◽  
Xiaomeng Liu ◽  
Chengjin Jin
Keyword(s):  
Radio Telescope ◽  
Field Of View ◽  
Array Configuration

Antenna Array Configuration in Holographic Microwave Imaging

2014 ◽  
Author(s):  
Lulu Wang ◽  
Ahmed Al-Jumaily ◽  
Ray Simpkin
Keyword(s):  
High Resolution ◽  
Antenna Array ◽  
Antenna Arrays ◽  
Biomedical Imaging ◽  
Microwave Imaging ◽  
Lesion Detection ◽  
Array Configuration ◽  
Random Array ◽  
Research Findings ◽  
Brain Stroke

Biomedical imaging has played an important role in identifying and monitoring the effectiveness of the current state of the art treatments for many diseases. We recently proposed a novel holographic microwave imaging array (HMIA) technique for lesion detection. One of the most important considerations of this technique is the antenna array configuration. This paper demonstrates investigation of using various antenna array configurations to generate a high-resolution microwave image by using the HMIA technique. Both simulation and experimental results are obtained and compared using spiral, random and regularly spaced array configurations to fully demonstrate the effectiveness of antenna arrays to the HMIA technique. The results show that the proposed spiral and random array configurations have the ability to produce high-resolution images at significantly lower cost compared to regularly spaced array. The potential biomedical imaging applications of the research findings would be breast cancer detection and/or brain stroke detection.

Interpretation of the Filament Depression at Millimetric and Centimetric Wavelengths

1979 ◽  
Vol 44 ◽  
pp. 131-134
Author(s):  
A. Raoult ◽  
P. Lantos ◽  
E. Fürst
Keyword(s):  
Radio Telescope ◽  
Active Regions ◽  
Simple Shape ◽  
Quiet Sun ◽  
Unstable Process

The depressions at centimetric and millimetric wavelengths associated with the filaments are studied using already published maps as well as unpublished observations from the Effelsberg 100 m radio telescope of the M.P.I., Bonn. The study has been restricted to large Ha quiescent prominences of relatively simple shape, situated far from the limb and from active regions. The data has been reduced employing one method whose main characteristics are choice of a local quiet sun definition and avoidance of the unstable process of deconvolution.

DISLOCATION RELAXATION IN A RANDOM ARRAY OF SOLUTES

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-319-C5-324 ◽  
Author(s):  
I. G. Ritchie ◽  
A. Atrens ◽  
C. B. So ◽  
K. W. Sprungmann
Keyword(s):  
Random Array

Measurements of radio telescope receiving system noise temperatures of two-elements radio interferometer with very long baseline

2018 ◽  
pp. 51-54
Author(s):  
I. E. Arsaev ◽  
Yu. V. Vekshin ◽  
A. I. Lapshin ◽  
V. V. Mardyshkin ◽  
M. V. Sargsyan ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Radio Interferometer ◽  
System Noise ◽  
Long Baseline

Analysis of AC-DC Converter Circuit Performance with Difference Piezoelectric Transducer Array Connection

2020 ◽  
Vol 12 (7) ◽  
Author(s):  
Nik Ahmad Zainal Abidin ◽  
◽  
Norkharziana Mohd Nayan ◽  
Azuwa Ali ◽  
N. A. Azli ◽  
...  
Keyword(s):  
Piezoelectric Transducer ◽  
Simulation Analysis ◽  
Piezoelectric Sensor ◽  
Transducer Array ◽  
Circuit Performance ◽  
Array Configuration ◽  
Full Wave ◽  
Bridge Rectifier ◽  
In Series ◽  
Parallel Voltage

This research presents a simulation analysis for the AC-DC converter circuit with a different configurations of the array connection of the piezoelectric sensor. The selection of AC-DC converter circuits is full wave bridge rectifier (FWBR), parallel SSHI (P-SSHI) and parallel voltage multiplier (PVM) with array configuration variation in series (S), parallel (P), series-parallel (SP) and parallel-series (PS). The system optimizes with different load configurations ranging from 10 kΩ to 1 MΩ. The best configuration of AC-DC converter with an appropriate array piezoelectric connection producing the optimum output of harvested power is presented. According to the simulation results, the harvested power produced by using P-SSHI converter connected with 3 parallel piezoelectric transducer array was 85.9% higher than for PVM and 15.88% higher than FWBR.

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