scholarly journals Optimized integrated design of a high-frequency medical ultrasound transducer with genetic algorithm

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Ali Babazadeh Khameneh ◽  
Hamid Reza Chabok ◽  
Hossein Nejat Pishkenari
Keyword(s):  
High Frequency ◽  
Focal Length ◽  
Integrated Design ◽  
Equivalent Circuit Model ◽  
Single Element ◽  
Optimized Design ◽  
Medical Ultrasound ◽  
Efficient Design ◽  
Daunting Task ◽  
Imaging Resolution

AbstractDesigning efficient acoustic stack and elements for high-frequency (HF) medical ultrasound (US) transducers involves various interrelated parameters. So far, optimizing spatial resolution and acoustic field intensity simultaneously has been a daunting task in the area of HF medical US imaging. Here, we introduce optimized design for a 50-MHz US probe for skin tissue imaging. We have developed an efficient design and simulation approach using Krimholtz, Leedom and Matthaei (KLM) equivalent circuit model and spatial impulse response method by means of Field II software. These KLM model and Field II software are integrated, and a GA algorithm is used to optimize the design of the US transducer to obtain the best imaging performance. As a result, a 50-MHz single element probe is effectively optimized with 5 mm acoustic focal length, 72 $$\upmu {\text{m}}$$ μ m lateral, and 42 $$\upmu {\text{m}}$$ μ m axial imaging resolution, with an enhancement in imaging resolution over the conventionally designed and simulated probe by 10%. This work has the potential to benefit many applications that require a fast, high-resolution and strong US focus in skin imaging.

scholarly journals Implementation of a Rotational Ultrasound Biomicroscopy System Equipped with a High-Frequency Angled Needle Transducer — Ex Vivo Ultrasound Imaging of Porcine Ocular Posterior Tissues

2021 ◽  
Author(s):  
Tae-Hoon Bok ◽  
Juho Kim ◽  
Jinho Bae ◽  
Chong Hyun Lee ◽  
Dong-Guk Paeng
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Ex Vivo ◽  
Focal Length ◽  
Ultrasound Biomicroscopy ◽  
Single Element ◽  
High Frequency Ultrasound ◽  
Scanning Angle ◽  
Distance Range ◽  
Minimal Incision

The mechanical scanning of a single element transducer has been mostly utilized for high-frequency ultrasound imaging. However, it requires space for the mechanical motion of the transducer. In this paper, a rotational scanning ultrasound biomicroscopy (UBM) system equipped with a high-frequency angled needle transducer is designed and implemented in order to minimize the space required. It was applied to ex vivo ultrasound imaging of porcine posterior ocular tissues through a minimal incision hole of 1 mm in diameter. The retina and sclera for the one eye were visualized in the relative rotating angle range of 270° ~ 330° and at a distance range of 6 ~ 7 mm, whereas the tissues of the other eye were observed in relative angle range of 160° ~ 220° and at a distance range of 7.5 ~ 9 mm. The layer between retina and sclera seemed to be bent because the distance between the transducer tip and the layer was varied while the transducer was rotated. Certin features of the rotation system such as the optimal scanning angle, step angle and data length need to be improved for ensure higher accuracy and precision. Moreover, the focal length should be considered for the image quality. This implementation represents the first report of a rotational scanning UBM system.

scholarly journals Implementation of a Rotational Ultrasound Biomicroscopy System Equipped with a High-Frequency Angled Needle Transducer — Ex Vivo Ultrasound Imaging of Porcine Ocular Posterior Tissues

2021 ◽  
Author(s):  
Tae-Hoon Bok ◽  
Juho Kim ◽  
Jinho Bae ◽  
Chong Hyun Lee ◽  
Dong-Guk Paeng
Keyword(s):  
Ultrasound Imaging ◽  
High Frequency ◽  
Ex Vivo ◽  
Focal Length ◽  
Ultrasound Biomicroscopy ◽  
Single Element ◽  
High Frequency Ultrasound ◽  
Scanning Angle ◽  
Distance Range ◽  
Minimal Incision

The mechanical scanning of a single element transducer has been mostly utilized for high-frequency ultrasound imaging. However, it requires space for the mechanical motion of the transducer. In this paper, a rotational scanning ultrasound biomicroscopy (UBM) system equipped with a high-frequency angled needle transducer is designed and implemented in order to minimize the space required. It was applied to ex vivo ultrasound imaging of porcine posterior ocular tissues through a minimal incision hole of 1 mm in diameter. The retina and sclera for the one eye were visualized in the relative rotating angle range of 270° ~ 330° and at a distance range of 6 ~ 7 mm, whereas the tissues of the other eye were observed in relative angle range of 160° ~ 220° and at a distance range of 7.5 ~ 9 mm. The layer between retina and sclera seemed to be bent because the distance between the transducer tip and the layer was varied while the transducer was rotated. Certin features of the rotation system such as the optimal scanning angle, step angle and data length need to be improved for ensure higher accuracy and precision. Moreover, the focal length should be considered for the image quality. This implementation represents the first report of a rotational scanning UBM system.

scholarly journals A High Frequency Geometric Focusing Transducer Based on 1-3 Piezocomposite for Intravascular Ultrasound Imaging

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaohua Jian ◽  
Zhile Han ◽  
Pengbo Liu ◽  
Jie Xu ◽  
Zhangjian Li ◽  
...  
Keyword(s):  
Intravascular Ultrasound ◽  
Ultrasound Imaging ◽  
High Frequency ◽  
High Sensitivity ◽  
Single Element ◽  
Small Aperture ◽  
Intravascular Ultrasound Imaging ◽  
Intensity Field ◽  
Imaging Resolution ◽  
Pulse Echo

Due to the small aperture of blood vessel, a considerable disadvantage to current intravascular ultrasound (IVUS) imaging transducers is that their lateral imaging resolution is much lower than their axial resolution. To solve this problem, a single-element, 50 MHz, 0.6 mm diameter IVUS transducer with a geometric focus at 3 mm was proposed in this paper. The focusing transducer was based on a geometric-shaped 1-3 piezocomposite. The impedance/phase, pulse echo, acoustic intensity field, and imaging resolution of the focusing transducer were tested. For comparison, a flat IVUS transducer with the same diameter and 1-3 piezocomposite was made and tested too. Compared with their results, the fabricated focusing transducer exhibits broad bandwidth (107.21%), high sensitivity (404 mV), high axial imaging resolution (80 μm), and lateral imaging resolution (100 μm). The experimental results demonstrated that the high frequency geometric focusing piezocomposite transducer is capable of visualizing high axial and lateral resolution structure and improving the imaging quality of related interventional ultrasound imaging.

Practical Design of a High Frequency Phased-Array Acoustic Microscope Probe: A Preliminary Study

2017 ◽  
Author(s):  
Jeong Nyeon Kim ◽  
Richard L. Tutwiler ◽  
Judith A. Todd
Keyword(s):  
High Frequency ◽  
Phased Array ◽  
Incident Angle ◽  
Focal Length ◽  
Acoustic Microscopy ◽  
Mode Shapes ◽  
Single Element ◽  
Acoustic Microscope ◽  
Acoustic Lens ◽  
Microscope Probe

Scanning acoustic microscopy (SAM) has been a well-recognized tool for both visualization and quantitative evaluation of materials at the microscale since its invention in 1974. While there have been multiple advances in SAM over the past four decades, some issues still remain to be addressed. First, the measurement speed is limited by the mechanical movement of the acoustic lens. Second, a single element transducer acoustic lens only delivers a predetermined beam pattern for a fixed focal length and incident angle, thereby limiting control of the inspection beam. Here, we propose to develop a phased-array probe as an alternative to overcome these issues. Preliminary studies to design a practical high frequency phased-array acoustic microscope probe were explored. A linear phased-array, comprising 32 elements and operating at 5 MHz, was modeled using PZFlex, a finite-element method software. This phased-array system was characterized in terms of electrical input impedance response, pulse-echo and impulse response, surface displacement profiles, mode shapes, and beam profiles. The results are presented in this paper.

scholarly journals A RF Redundant TSV Interconnection for High Resistance Si Interposer

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 169
Author(s):  
Mengcheng Wang ◽  
Shenglin Ma ◽  
Yufeng Jin ◽  
Wei Wang ◽  
Jing Chen ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
High Frequency ◽  
High Performance ◽  
Rapid Development ◽  
Coplanar Waveguide ◽  
Equivalent Circuit Model ◽  
High Resistivity ◽  
Performance Requirements ◽  
Wave Radar ◽  
Interconnect Design

Through Silicon Via (TSV) technology is capable meeting effective, compact, high density, high integration, and high-performance requirements. In high-frequency applications, with the rapid development of 5G and millimeter-wave radar, the TSV interposer will become a competitive choice for radio frequency system-in-package (RF SIP) substrates. This paper presents a redundant TSV interconnect design for high resistivity Si interposers for millimeter-wave applications. To verify its feasibility, a set of test structures capable of working at millimeter waves are designed, which are composed of three pieces of CPW (coplanar waveguide) lines connected by single TSV, dual redundant TSV, and quad redundant TSV interconnects. First, HFSS software is used for modeling and simulation, then, a modified equivalent circuit model is established to analysis the effect of the redundant TSVs on the high-frequency transmission performance to solidify the HFSS based simulation. At the same time, a failure simulation was carried out and results prove that redundant TSV can still work normally at 44 GHz frequency when failure occurs. Using the developed TSV process, the sample is then fabricated and tested. Using L-2L de-embedding method to extract S-parameters of the TSV interconnection. The insertion loss of dual and quad redundant TSVs are 0.19 dB and 0.46 dB at 40 GHz, respectively.

scholarly journals Synchronous Machine Winding Modeling Method Based on Broadband Characteristics

2021 ◽  
Vol 11 (10) ◽  
pp. 4631
Author(s):  
Yu Chen ◽  
Xiaoqing Ji ◽  
Zhongyong Zhao
Keyword(s):  
Equivalent Circuit ◽  
High Frequency ◽  
Equivalent Circuit Model ◽  
Black Box ◽  
Synchronous Machine ◽  
Circuit Model ◽  
Modeling Method ◽  
Experimental Results ◽  
Box Model ◽  
Impedance Curve

The accurate establishment of the equivalent circuit model of the synchronous machine windings’ broadband characteristics is the basis for the study of high-frequency machine problems, such as winding fault diagnosis and electromagnetic interference prediction. Therefore, this paper proposes a modeling method for synchronous machine winding based on broadband characteristics. Firstly, the single-phase high-frequency lumped parameter circuit model of synchronous machine winding is introduced, then the broadband characteristics of the port are analyzed by using the state space model, and then the equivalent circuit parameters are identified by using an optimization algorithm combined with the measured broadband impedance characteristics of port. Finally, experimental verification and comparison experiments are carried out on a 5-kW synchronous machine. The experimental results show that the proposed modeling method identifies the impedance curve of the circuit parameters with a high degree of agreement with the measured impedance curve, which indicates that the modeling method is feasible. In addition, the comparative experimental results show that, compared with the engineering exploratory calculation method, the proposed parameter identification method has stronger adaptability to the measured data and a certain robustness. Compared with the black box model, the parameters of the proposed model have a certain physical meaning, and the agreement with the actual impedance characteristic curve is higher than that of the black box model.

scholarly journals An Antenna-Theory Method for Modeling High-Frequency RF Coils: A Segmented Birdcage Example

2008 ◽  
Vol 2008 ◽  
pp. 1-10 ◽  
Author(s):  
Xin Chen ◽  
Victor Taracila ◽  
Timothy Eagan ◽  
Hiroyuki Fujita ◽  
Xingxian Shou ◽  
...  
Keyword(s):  
High Frequency ◽  
Dipole Antenna ◽  
Rf Coils ◽  
Optimized Design ◽  
Theory Method ◽  
Rf Coil ◽  
Field Approach ◽  
Antenna Theory ◽  
Target Field ◽  
Tem Mode

We suggest that center-fed dipole antenna analytics can be employed in the optimized design of high-frequency MRI RF coil applications. The method is illustrated in the design of a single-segmented birdcage model and a short multisegmented birdcage model. As a byproduct, it is shown that for a long single-segmented birdcage model, the RF field within it is essentially a TEM mode and has excellent planar uniformity. For a short shielded multisegmented birdcage model, the RF field is optimized with a target-field approach with an average SAR functional. The planar homogeneity of the optimized RF field is significantly improved compared with that of a single-segmented birdcage model with the same geometry. The accuracy of the antenna formulae is also verified with numerical simulations performed via commercial software. The model discussed herein provides evidence for the effectiveness of antenna methods in future RF coil analysis.

Design, fabrication, and evaluation of high frequency, single-element transducers incorporating different materials

2002 ◽  
Vol 49 (2) ◽  
pp. 169-176 ◽  
Author(s):  
K.A. Snook ◽  
Jian-Zhong Zhao ◽  
C.H.F. Alves ◽  
J.M. Cannata ◽  
Wo-Hsing Chen ◽  
...  
Keyword(s):  
High Frequency ◽  
Single Element

scholarly journals Synthetic Aperture Imaging Using High-Frequency Convex Array for Ophthalmic Ultrasound Applications

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2275
Author(s):  
Hae Gyun Lim ◽  
Hyung Ham Kim ◽  
Changhan Yoon
Keyword(s):  
Image Quality ◽  
Penetration Depth ◽  
Spatial Resolution ◽  
High Frequency ◽  
Imaging System ◽  
Ex Vivo ◽  
Synthetic Aperture ◽  
Single Element ◽  
High Frequency Ultrasound ◽  
Synthetic Aperture Imaging

High-frequency ultrasound (HFUS) imaging has emerged as an essential tool for pre-clinical studies and clinical applications such as ophthalmic and dermatologic imaging. HFUS imaging systems based on array transducers capable of dynamic receive focusing have considerably improved the image quality in terms of spatial resolution and signal-to-noise ratio (SNR) compared to those by the single-element transducer-based one. However, the array system still suffers from low spatial resolution and SNR in out-of-focus regions, resulting in a blurred image and a limited penetration depth. In this paper, we present synthetic aperture imaging with a virtual source (SA-VS) for an ophthalmic application using a high-frequency convex array transducer. The performances of the SA-VS were evaluated with phantom and ex vivo experiments in comparison with the conventional dynamic receive focusing method. Pre-beamformed radio-frequency (RF) data from phantoms and excised bovine eye were acquired using a custom-built 64-channel imaging system. In the phantom experiments, the SA-VS method showed improved lateral resolution (>10%) and sidelobe level (>4.4 dB) compared to those by the conventional method. The SNR was also improved, resulting in an increased penetration depth: 16 mm and 23 mm for the conventional and SA-VS methods, respectively. Ex vivo images with the SA-VS showed improved image quality at the entire depth and visualized structures that were obscured by noise in conventional imaging.

scholarly journals Transfer of diclofenac sodium across excised guinea pig skin on high-frequency pulse iontophoresis. I. Equivalent circuit model.

1990 ◽  
Vol 38 (4) ◽  
pp. 1019-1021 ◽  
Author(s):  
Tamotsu KOIZUMI ◽  
Masawa KAKEMI ◽  
Kazunori KATAYAMA ◽  
Hirohiko INADA ◽  
Kazuyoshi SUDEJI ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Equivalent Circuit ◽  
High Frequency ◽  
Diclofenac Sodium ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Pig Skin ◽  
Frequency Pulse
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