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.

scholarly journals Array antennas design in dependence of element-phasing

2009 ◽  
Vol 7 ◽  
pp. 267-271
Author(s):  
R. Zichner ◽  
M. Chandra
Keyword(s):  
Radiation Characteristic ◽  
Phase Behaviour ◽  
Beam Forming ◽  
Antenna Element ◽  
Array Configuration ◽  
Array Pattern ◽  
Array Antennas ◽  
Gps Satellites ◽  
Forming Behaviour ◽  
Insight Into

Abstract. Array antennas are used in science as well as for commercial and military purposes. The used element antennas act in accordance to their desired uses, for example radars or stationer GPS satellites. Typical components are for example slotted waveguides, patches, yagi-antennas and helix-antennas. All these elements do stand out with their own characteristics based on their special applications. If these elements are formed into an array configuration, the effectiveness can be improved immensely. There is a relation between the array functions and the physical array properties like the element alignment (linear, planar, circular), distances between the elements and so on. Among the physical properties there are other attributes like phase or amplitude coefficients, which are of great significance. The aim of this study was to provide an insight into the problem of array design, as far as the antenna element phase is concerned. Along with this, array radiation characteristics effects are presented. With the help of the extracted cognitions beam forming behaviour can be shown and the array phase behaviour can be analysed. One of the main applications is to simulate the array characteristics, like the radiation characteristic or the gain, for displacements of the array feeding point. A software solution that simulates the phase shift of a given array pattern is sought to adjust the feeding point.

scholarly journals Sensitivity Analysis of a Beamforming Technique for Acoustic Measurements

2021 ◽  
Author(s):  
Pushpinder Singh Bhullar
Keyword(s):  
Linear Array ◽  
Sound Level ◽  
Acoustic Measurements ◽  
Acoustic Source ◽  
Uniform Linear Array ◽  
Random Array ◽  
Planar Array ◽  
Simulation Results ◽  
Spiral Array ◽  
Beamforming Technique

Beamforming is a technique that is used to determine the location of an acoustic source and the sound level spectrum of the signal produced by the source. This technique involves an array of microphones which record acoustic signals at multiple locations. A detailed analysis of the beamforming technique was carried out for three different array geometries: a uniform linear array, a uniform planar array, and a random array. The effect of various parameters, such as the number of microphones in an array, on the applicability of the technique was examined using both simulations and experiments. The simulation results established that the source localization capability of a uniform linear array is limited to an acoustic source lying in the plane of the array. In contrast, a planar array (either uniform or random) does not suffer the above limitation. The results also showed that a random array (eg., a spiral array) is the best of all the array geometries. The experimental results demonstrated the robustness of the beamforming technique in localizing an acoustic source and also confirmed the superiority of a uniform planar array over a uniform linear array.

scholarly journals Lift-off Effect for Capacitive Imaging Sensors

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4286 ◽  
Author(s):  
Xiaokang Yin ◽  
Chen Li ◽  
Zhen Li ◽  
Wei Li ◽  
Guoming Chen
Keyword(s):  
Fibre Composite ◽  
Dielectric Materials ◽  
Hybrid Structure ◽  
Fe Analysis ◽  
Measurement Sensitivity ◽  
Capacitance Variation ◽  
Complex Measurement ◽  
Lift Off ◽  
Imaging Sensors ◽  
Imaging Performance

Capacitive Imaging (CI) sensors are capable of non-detecting both surface and hidden defects in dielectric materials and characterizing conducting surfaces through a relatively thick insulation layer. However, the complex Measurement Sensitivity Distribution (MSD) of CI sensors render the sensor capacitance variation with lift-off highly non-linear, which may lead to misinterpretation of defect indications. This work systematically studied the lift-off effect using both Finite Element (FE) analysis and experimental approaches. Sensor MSD was used as a tool to predict the imaging performance. Normalized Variation Ratio (NVR) was introduced and used to characterise sensor responses due to defects for a CI sensor. Both the FE analysis and experiments suggest that the lift-off effect for a CI sensor is specimen type and condition dependent. For a given defect, the NVR may vary non-monotonically with increased lift-offs. A case study on a glass-fibre composite/aluminium hybrid structure with multiple artificial defects demonstrated the feasibility of defects discrimination using multiple CI scans with increased lift-offs.

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.

scholarly journals Sensitivity Analysis of a Beamforming Technique for Acoustic Measurements

2021 ◽  
Author(s):  
Pushpinder Singh Bhullar
Keyword(s):  
Linear Array ◽  
Sound Level ◽  
Acoustic Measurements ◽  
Acoustic Source ◽  
Uniform Linear Array ◽  
Random Array ◽  
Planar Array ◽  
Simulation Results ◽  
Spiral Array ◽  
Beamforming Technique

Beamforming is a technique that is used to determine the location of an acoustic source and the sound level spectrum of the signal produced by the source. This technique involves an array of microphones which record acoustic signals at multiple locations. A detailed analysis of the beamforming technique was carried out for three different array geometries: a uniform linear array, a uniform planar array, and a random array. The effect of various parameters, such as the number of microphones in an array, on the applicability of the technique was examined using both simulations and experiments. The simulation results established that the source localization capability of a uniform linear array is limited to an acoustic source lying in the plane of the array. In contrast, a planar array (either uniform or random) does not suffer the above limitation. The results also showed that a random array (eg., a spiral array) is the best of all the array geometries. The experimental results demonstrated the robustness of the beamforming technique in localizing an acoustic source and also confirmed the superiority of a uniform planar array over a uniform linear array.

Effects of array transducer inconsistencies on total focusing method imaging performance

2011 ◽  
Vol 44 (4) ◽  
pp. 361-368 ◽  
Author(s):  
Jie Zhang ◽  
Bruce W. Drinkwater ◽  
Paul D. Wilcox
Keyword(s):  
Array Transducer ◽  
Imaging Performance

scholarly journals Phased-Array Transducer for Intracardiac Echocardiography Based on 1–3 Piezocomposite

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhile Han ◽  
Ninghao Wang ◽  
Zhangjian Li ◽  
Xinle Zhu ◽  
Youwei Chen ◽  
...  
Keyword(s):  
Phased Array ◽  
Lower Surface ◽  
Intracardiac Echocardiography ◽  
Circuit Board ◽  
Center Frequency ◽  
Array Transducer ◽  
Ultrasonic Phased Array ◽  
Single Use ◽  
Compact Design ◽  
Imaging Performance

In this study, an ultrasonic phased-array transducer was proposed, which could effectively improve the imaging performance by using 1–3 piezocomposite. The piezocomposite consists of PZT and epoxy, with a pitch of 70 μm, kerf of 20 μm, and thickness of 170 μm. The phased-array transducer has 64 elements; the size of each element is 85 μm × 1.3 mm; the pitch of the transducer is 100 μm; and the kerf between the elements is only 15 μm. To minimize the transducer size, the 1–3 composite uses an encase structure, which connects the upper surface of the composite directly to the flexible circuit board bonded to the lower surface as the ground electrode. The size of the final fabricated transducer is 2 mm × 7.4 mm, and the transducer is mounted on a 9 F (3 mm diameter) catheter, which can bend in four directions and is primarily used for intracardiac echocardiography (ICE). The acoustic and electrical properties of the transducer were tested, including impedance, echo sensitivity, center frequency (9 MHz), bandwidth (BW) (55%), and consistency. Finally, the wire phantom experiments were carried out to demonstrate the spatial resolutions and imaging performance. This study shows that this transducer with compact design and construction can bring higher performance for the single-use disposable ICE catheter.

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