Pub Date : 2022-09-15DOI: 10.1109/OJUFFC.2022.3207128
Sina Sadeghpour;Sanjog Vilas Joshi;Chen Wang;Michael Kraft
Two kinds of 128 channels pMUT-based phased array ultrasound transducers are described in this paper, one with a high frequency of around 6 MHz and another with a low frequency of around 1.5 MHz. The active area of the transducer is around 25 mm long and 10 mm wide. There are in total 6270 pMUT elements in the reported arrays. For the transducer with a center frequency of 6 MHz, each pMUT has a membrane diameter of 85 $mu text{m}$ and the pitch between every two channels is 200 $mu text{m}$ . The transducer benefits from a high transmission and receive sensitivity of 44 kPa/V/Channel @ 3 cm and 204 mV/MPa, respectively. For the transducer with a center frequency of 1.5 MHz, each pMUT has a membrane diameter of $160~mu text{m}$ and the pitch between every two elements is 214 $mu text{m}$ . The proposed transducer obtained a transmit and receive sensitivity of 430 Pa/V/Channel @ 3 cm and 190 mV/MPa, respectively. The transducer has a −3dB and −6dB bandwidth of 118% and 184%, respectively. The bandwidth is higher than any previously reported transducer in any technology, such as bulk-PZT, pMUT, or capacitive MUT (cMUT). The functionality of the transducer arrays is confirmed by obtaining B-mode images in water medium.
{"title":"Novel Phased Array Piezoelectric Micromachined Ultrasound Transducers (pMUTs) for Medical Imaging","authors":"Sina Sadeghpour;Sanjog Vilas Joshi;Chen Wang;Michael Kraft","doi":"10.1109/OJUFFC.2022.3207128","DOIUrl":"10.1109/OJUFFC.2022.3207128","url":null,"abstract":"Two kinds of 128 channels pMUT-based phased array ultrasound transducers are described in this paper, one with a high frequency of around 6 MHz and another with a low frequency of around 1.5 MHz. The active area of the transducer is around 25 mm long and 10 mm wide. There are in total 6270 pMUT elements in the reported arrays. For the transducer with a center frequency of 6 MHz, each pMUT has a membrane diameter of 85 \u0000<inline-formula> <tex-math>$mu text{m}$ </tex-math></inline-formula>\u0000 and the pitch between every two channels is 200 \u0000<inline-formula> <tex-math>$mu text{m}$ </tex-math></inline-formula>\u0000. The transducer benefits from a high transmission and receive sensitivity of 44 kPa/V/Channel @ 3 cm and 204 mV/MPa, respectively. For the transducer with a center frequency of 1.5 MHz, each pMUT has a membrane diameter of \u0000<inline-formula> <tex-math>$160~mu text{m}$ </tex-math></inline-formula>\u0000 and the pitch between every two elements is 214 \u0000<inline-formula> <tex-math>$mu text{m}$ </tex-math></inline-formula>\u0000. The proposed transducer obtained a transmit and receive sensitivity of 430 Pa/V/Channel @ 3 cm and 190 mV/MPa, respectively. The transducer has a −3dB and −6dB bandwidth of 118% and 184%, respectively. The bandwidth is higher than any previously reported transducer in any technology, such as bulk-PZT, pMUT, or capacitive MUT (cMUT). The functionality of the transducer arrays is confirmed by obtaining B-mode images in water medium.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"194-202"},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9893177","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62907407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-16DOI: 10.1109/OJUFFC.2022.3197104
Tony Merrien;Audren Boulmé;Dominique Certon
Thermal-Mechanical (T-M) noise is a natural phenomenon occurring in Capacitive Micromachined Ultrasonic Transducers (CMUT). T-M noise is a value of great interest because it is linked to the minimal detectable pressure of a transducer and can also serve as a convenient characterization tool. Indeed, the general behavior of a CMUT array is translated through its T-M noise which does not require any external applied source to be assessed. However, T-M noise is difficult to measure, often time requires a dedicated measurement chain and is mostly based on spectrum analyzers in a carefully controlled environment. In this paper, we present a temporal technique to characterize the T-M noise of CMUT-based arrays with a commercially available amplifier and a digital oscilloscope. The approach is applied to an air coupled Row-Column Addressed (RCA) matrix array, for which the elements cannot be measured with traditional micro-probes systems. This task is performed using a Printed Circuit Board (PCB) dedicated to the characterization of RCA arrays and designed to drive rows and columns individually. Noise Power Spectral Density (PSD) modeling of the complete measurement chain is achieved using a lumped-parameter model of the RCA array element and using the amplifier gain, electrical impedance, and noise characteristics. Measurements obtained with the signal analyzer and the temporal method are in good agreement with the model. The presented characterization technique can be extended to other micromachined ultrasonic transducer probe architectures, technologies, and amplification systems.
{"title":"Thermal-Mechanical Noise Modeling and Measurements of a Row-Column Addressed CMUT Probe","authors":"Tony Merrien;Audren Boulmé;Dominique Certon","doi":"10.1109/OJUFFC.2022.3197104","DOIUrl":"10.1109/OJUFFC.2022.3197104","url":null,"abstract":"Thermal-Mechanical (T-M) noise is a natural phenomenon occurring in Capacitive Micromachined Ultrasonic Transducers (CMUT). T-M noise is a value of great interest because it is linked to the minimal detectable pressure of a transducer and can also serve as a convenient characterization tool. Indeed, the general behavior of a CMUT array is translated through its T-M noise which does not require any external applied source to be assessed. However, T-M noise is difficult to measure, often time requires a dedicated measurement chain and is mostly based on spectrum analyzers in a carefully controlled environment. In this paper, we present a temporal technique to characterize the T-M noise of CMUT-based arrays with a commercially available amplifier and a digital oscilloscope. The approach is applied to an air coupled Row-Column Addressed (RCA) matrix array, for which the elements cannot be measured with traditional micro-probes systems. This task is performed using a Printed Circuit Board (PCB) dedicated to the characterization of RCA arrays and designed to drive rows and columns individually. Noise Power Spectral Density (PSD) modeling of the complete measurement chain is achieved using a lumped-parameter model of the RCA array element and using the amplifier gain, electrical impedance, and noise characteristics. Measurements obtained with the signal analyzer and the temporal method are in good agreement with the model. The presented characterization technique can be extended to other micromachined ultrasonic transducer probe architectures, technologies, and amplification systems.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"162-172"},"PeriodicalIF":0.0,"publicationDate":"2022-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9857839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62907678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-11DOI: 10.1109/OJUFFC.2022.3198390
Monica La Mura;Alvise Bagolini;Patrizia Lamberti;Alessandro Stuart Savoia
This paper addresses the assessment of the variability of CMUT arrays’ electro-mechanical and acoustic performance, as related to the tolerance of the CMUT vertical dimensions due to the microfabrication process. A 3-factors 3-levels factorial sensitivity analysis is carried out to compute the main effects and the interaction effects of the moving plate thickness, the passivation layers thickness, and the sacrificial layer thickness, on the CMUT resonance frequency, collapse voltage, and static capacitance, as well as on the transmission and reception sensitivity amplitude and bandwidth and time delay in water-coupled condition. The analysis is performed by means of FEM simulations of the CMUT static behavior and dynamic response, and the findings are compared to experimental data.
{"title":"Assessing the Microfabrication-Related Variability of the Performance of CMUT Arrays","authors":"Monica La Mura;Alvise Bagolini;Patrizia Lamberti;Alessandro Stuart Savoia","doi":"10.1109/OJUFFC.2022.3198390","DOIUrl":"10.1109/OJUFFC.2022.3198390","url":null,"abstract":"This paper addresses the assessment of the variability of CMUT arrays’ electro-mechanical and acoustic performance, as related to the tolerance of the CMUT vertical dimensions due to the microfabrication process. A 3-factors 3-levels factorial sensitivity analysis is carried out to compute the main effects and the interaction effects of the moving plate thickness, the passivation layers thickness, and the sacrificial layer thickness, on the CMUT resonance frequency, collapse voltage, and static capacitance, as well as on the transmission and reception sensitivity amplitude and bandwidth and time delay in water-coupled condition. The analysis is performed by means of FEM simulations of the CMUT static behavior and dynamic response, and the findings are compared to experimental data.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"173-183"},"PeriodicalIF":0.0,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9855522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62907817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-05DOI: 10.1109/OJUFFC.2022.3196823
Pannawit Tipsawat;Sheikh Jawad Ilham;Jung In Yang;Zeinab Kashani;Mehdi Kiani;Susan Trolier-Mckinstry
Interest in utilizing ultrasound (US) transducers for non-invasive neuromodulation treatment, including for low intensity transcranial focused ultrasound stimulation (tFUS), has grown rapidly. The most widely demonstrated US transducers for tFUS are either bulk piezoelectric transducers or capacitive micromachine transducers (CMUT) which require high voltage excitation to operate. In order to advance the development of the US transducers towards small, portable devices for safe tFUS at large scale, a low voltage array of US transducers with beam focusing and steering capability is of interest. This work presents the design methodology, fabrication, and characterization of 32-element phased array piezoelectric micromachined ultrasound transducers (PMUT) using $1.5~mu text{m}$ thick Pb(Zr 0.52 Ti $_{{mathrm {0.48}}})text{O}_{3}$ films doped with 2 mol% Nb. The electrode/piezoelectric/electrode stack was deposited on a silicon on insulator (SOI) wafer with a $2~mu text{m}$ silicon device layer that serves as the passive elastic layer for bending-mode vibration. The fabricated 32-element PMUT has a central frequency at 1.4 MHz. Ultrasound beam focusing and steering (through beamforming) was demonstrated where the array was driven with 14.6 V square unipolar pulses. The PMUT generated a maximum peak-to-peak focused acoustic pressure output of 0.44 MPa at a focal distance of 20 mm with a 9.2 mm and 1 mm axial and lateral resolution, respectively. The maximum pressure is equivalent to a spatial-peak pulse-average intensity of 1.29 W/cm 2 , which is suitable for tFUS application.
{"title":"32 Element Piezoelectric Micromachined Ultrasound Transducer (PMUT) Phased Array for Neuromodulation","authors":"Pannawit Tipsawat;Sheikh Jawad Ilham;Jung In Yang;Zeinab Kashani;Mehdi Kiani;Susan Trolier-Mckinstry","doi":"10.1109/OJUFFC.2022.3196823","DOIUrl":"10.1109/OJUFFC.2022.3196823","url":null,"abstract":"Interest in utilizing ultrasound (US) transducers for non-invasive neuromodulation treatment, including for low intensity transcranial focused ultrasound stimulation (tFUS), has grown rapidly. The most widely demonstrated US transducers for tFUS are either bulk piezoelectric transducers or capacitive micromachine transducers (CMUT) which require high voltage excitation to operate. In order to advance the development of the US transducers towards small, portable devices for safe tFUS at large scale, a low voltage array of US transducers with beam focusing and steering capability is of interest. This work presents the design methodology, fabrication, and characterization of 32-element phased array piezoelectric micromachined ultrasound transducers (PMUT) using \u0000<inline-formula> <tex-math>$1.5~mu text{m}$ </tex-math></inline-formula>\u0000 thick Pb(Zr\u0000<sub>0.52</sub>\u0000Ti\u0000<inline-formula> <tex-math>$_{{mathrm {0.48}}})text{O}_{3}$ </tex-math></inline-formula>\u0000 films doped with 2 mol% Nb. The electrode/piezoelectric/electrode stack was deposited on a silicon on insulator (SOI) wafer with a \u0000<inline-formula> <tex-math>$2~mu text{m}$ </tex-math></inline-formula>\u0000 silicon device layer that serves as the passive elastic layer for bending-mode vibration. The fabricated 32-element PMUT has a central frequency at 1.4 MHz. Ultrasound beam focusing and steering (through beamforming) was demonstrated where the array was driven with 14.6 V square unipolar pulses. The PMUT generated a maximum peak-to-peak focused acoustic pressure output of 0.44 MPa at a focal distance of 20 mm with a 9.2 mm and 1 mm axial and lateral resolution, respectively. The maximum pressure is equivalent to a spatial-peak pulse-average intensity of 1.29 W/cm\u0000<sup>2</sup>\u0000, which is suitable for tFUS application.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"184-193"},"PeriodicalIF":0.0,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10021572/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9155513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Data-over-sound is an emerging technology for digital communication which uses frequencies at the upper bounds of human hearing, usually between 15 kHz to 25 kHz. We report a successful development of Piezoelectric Micromachined Ultrasound Transducers (PMUTs) for low-power data-over-sound applications. Piezoelectric thin films used in PMUTs can have high residual tensile stresses ranging from 300 MPa to 1.5 GPa. These stresses have the effect of increasing the resonant frequencies of the transducers, making it a challenge to fabricate low frequency devices. Using the optimum dimensions by estimating the net residual stress in the fabricated diaphragms, transducers suitable for a frequency range of 17 kHz to 21 kHz were fabricated, capable of generating as much as 83 dB of sound pressure level at a distance of 5 cm in continuous operation.
{"title":"Data-Over-Sound With PMUTs","authors":"Harshvardhan Gupta;Bibhas Nayak;Anuj Ashok;Rudra Pratap","doi":"10.1109/OJUFFC.2022.3197126","DOIUrl":"10.1109/OJUFFC.2022.3197126","url":null,"abstract":"Data-over-sound is an emerging technology for digital communication which uses frequencies at the upper bounds of human hearing, usually between 15 kHz to 25 kHz. We report a successful development of Piezoelectric Micromachined Ultrasound Transducers (PMUTs) for low-power data-over-sound applications. Piezoelectric thin films used in PMUTs can have high residual tensile stresses ranging from 300 MPa to 1.5 GPa. These stresses have the effect of increasing the resonant frequencies of the transducers, making it a challenge to fabricate low frequency devices. Using the optimum dimensions by estimating the net residual stress in the fabricated diaphragms, transducers suitable for a frequency range of 17 kHz to 21 kHz were fabricated, capable of generating as much as 83 dB of sound pressure level at a distance of 5 cm in continuous operation.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"152-161"},"PeriodicalIF":0.0,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9851658","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62907754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-08DOI: 10.1109/OJUFFC.2022.3184056
Stewart Sherrit;Mircea Badescu;John B. Steeves;William E. Krieger;Clifford A. Klein;Otto R. Polanco;Carey Louise Weisberg;David Van Buren;Joseph Sauvageau;Keith Coste
In the above article [1] , on the top line in Table 3 , a decimal place was dropped in the piezoelectric charge coefficient d 33 ( $mu$ m/V) at 100 K. The data reported is 10 times larger than the measured data from the slope in Figure 6 for all three maximum voltages. Here, we provide the correct table.
{"title":"Erratum to “Characterization of Multilayer Piezoelectric Stacks Down to 100K” [2022 65-82]","authors":"Stewart Sherrit;Mircea Badescu;John B. Steeves;William E. Krieger;Clifford A. Klein;Otto R. Polanco;Carey Louise Weisberg;David Van Buren;Joseph Sauvageau;Keith Coste","doi":"10.1109/OJUFFC.2022.3184056","DOIUrl":"https://doi.org/10.1109/OJUFFC.2022.3184056","url":null,"abstract":"In the above article \u0000<xref>[1]</xref>\u0000, on the top line in \u0000<xref>Table 3</xref>\u0000, a decimal place was dropped in the piezoelectric charge coefficient d\u0000<sub>33</sub>\u0000(\u0000<inline-formula> <tex-math>$mu$ </tex-math></inline-formula>\u0000m/V) at 100 K. The data reported is 10 times larger than the measured data from the slope in Figure 6 for all three maximum voltages. Here, we provide the correct table.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"105-105"},"PeriodicalIF":0.0,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9823363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137450654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-08DOI: 10.1109/OJUFFC.2022.3188746
Jianzhong Chen;Wei Liu;Dawei Wu;Hu Ye
Flexible ultrasound array with phased array configurations have individually controllable array element emission and reception acoustic properties, however array conventional processes and array design are too complex. It is necessary to explore rapid creation methods and potential ultrasound applications for flexible arrays. In this paper, we provide a method for rapid fabrication of flexible transducers based on laser micromachining and verify the performance of the line array by multi-mode positioning imaging under curved surfaces. The proposed single-layered and double-sided conductive stretchable electrode configuration eliminated the blockage of acoustic waves,and ’island bridge’ structures are compatible with array flexibility and array excitation for row addressing.The mechanical, acoustic and electrical interconnections of the array are verified.Based on the Verasonics system, the ultrasonic line array scans multiple steel column targets in multiple modalities under curved surfaces for imaging and localization.The results show that the ultrasonic line array can obtain clear visual localization images in A-scan, B-scan and E-scan poses.In addition, the artifacts in the images can be effectively suppressed by adjusting the depth of focus of E-scan and optimizing the sparse line array structure. It is verified that laser micromachining for rapid creation of flexible ultrasonic line array has potential applications in the field of localization imaging.
{"title":"Laser Micromachined Flexible Ultrasound Line Array and Subplanar Multimodal Imaging Applications","authors":"Jianzhong Chen;Wei Liu;Dawei Wu;Hu Ye","doi":"10.1109/OJUFFC.2022.3188746","DOIUrl":"10.1109/OJUFFC.2022.3188746","url":null,"abstract":"Flexible ultrasound array with phased array configurations have individually controllable array element emission and reception acoustic properties, however array conventional processes and array design are too complex. It is necessary to explore rapid creation methods and potential ultrasound applications for flexible arrays. In this paper, we provide a method for rapid fabrication of flexible transducers based on laser micromachining and verify the performance of the line array by multi-mode positioning imaging under curved surfaces. The proposed single-layered and double-sided conductive stretchable electrode configuration eliminated the blockage of acoustic waves,and ’island bridge’ structures are compatible with array flexibility and array excitation for row addressing.The mechanical, acoustic and electrical interconnections of the array are verified.Based on the Verasonics system, the ultrasonic line array scans multiple steel column targets in multiple modalities under curved surfaces for imaging and localization.The results show that the ultrasonic line array can obtain clear visual localization images in A-scan, B-scan and E-scan poses.In addition, the artifacts in the images can be effectively suppressed by adjusting the depth of focus of E-scan and optimizing the sparse line array structure. It is verified that laser micromachining for rapid creation of flexible ultrasonic line array has potential applications in the field of localization imaging.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"131-139"},"PeriodicalIF":0.0,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9819962","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62907032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-21DOI: 10.1109/OJUFFC.2022.3184909
Will Long;David Bradway;Rifat Ahmed;James Long;Gregg E. Trahey
Conventional color flow processing is associated with a high degree of operator dependence, often requiring the careful tuning of clutter filters and priority encoding to optimize the display and accuracy of color flow images. In a companion paper, we introduced a novel framework to adapt color flow processing based on local measurements of backscatter spatial coherence. Through simulation studies, the adaptive selection of clutter filters using coherence image quality characterization was demonstrated as a means to dynamically suppress weakly-coherent clutter while preserving coherent flow signal in order to reduce velocity estimation bias. In this study, we extend previous work to evaluate the application of coherence-adaptive clutter filtering (CACF) on experimental data acquired from both phantom and in vivo liver and fetal vessels. In phantom experiments with clutter-generating tissue, CACF was shown to increase the dynamic range of velocity estimates and decrease bias and artifact from flash and thermal noise relative to conventional color flow processing. Under in vivo conditions, such properties allowed for the direct visualization of vessels that would have otherwise required fine-tuning of filter cutoff and priority thresholds with conventional processing. These advantages are presented alongside various failure modes identified in CACF as well as discussions of solutions to mitigate such limitations.
{"title":"Spatial Coherence Adaptive Clutter Filtering in Color Flow Imaging—Part II: Phantom and In Vivo Experiments","authors":"Will Long;David Bradway;Rifat Ahmed;James Long;Gregg E. Trahey","doi":"10.1109/OJUFFC.2022.3184909","DOIUrl":"10.1109/OJUFFC.2022.3184909","url":null,"abstract":"Conventional color flow processing is associated with a high degree of operator dependence, often requiring the careful tuning of clutter filters and priority encoding to optimize the display and accuracy of color flow images. In a companion paper, we introduced a novel framework to adapt color flow processing based on local measurements of backscatter spatial coherence. Through simulation studies, the adaptive selection of clutter filters using coherence image quality characterization was demonstrated as a means to dynamically suppress weakly-coherent clutter while preserving coherent flow signal in order to reduce velocity estimation bias. In this study, we extend previous work to evaluate the application of coherence-adaptive clutter filtering (CACF) on experimental data acquired from both phantom and \u0000<italic>in vivo</i>\u0000 liver and fetal vessels. In phantom experiments with clutter-generating tissue, CACF was shown to increase the dynamic range of velocity estimates and decrease bias and artifact from flash and thermal noise relative to conventional color flow processing. Under \u0000<italic>in vivo</i>\u0000 conditions, such properties allowed for the direct visualization of vessels that would have otherwise required fine-tuning of filter cutoff and priority thresholds with conventional processing. These advantages are presented alongside various failure modes identified in CACF as well as discussions of solutions to mitigate such limitations.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"119-130"},"PeriodicalIF":0.0,"publicationDate":"2022-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9881236/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10592053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-21DOI: 10.1109/OJUFFC.2022.3184914
Will Long;David Bradway;Rifat Ahmed;James Long;Gregg E. Trahey
The appropriate selection of a clutter filter is critical for ensuring the accuracy of velocity estimates in ultrasound color flow imaging. Given the complex spatio-temporal dynamics of flow signal and clutter, however, the manual selection of filters can be a significant challenge, increasing the risk for bias and variance introduced by the removal of flow signal and/or poor clutter suppression. We propose a novel framework to adaptively select clutter filter settings based on color flow image quality feedback derived from the spatial coherence of ultrasonic backscatter. This framework seeks to relax assumptions of clutter magnitude and velocity that are traditionally required in existing adaptive filtering methods to generalize clutter filtering to a wider range of clinically-relevant color flow imaging conditions. In this study, the relationship between color flow velocity estimation error and the spatial coherence of clutter filtered channel signals was investigated in Field II simulations for a wide range of flow and clutter conditions. This relationship was leveraged in a basic implementation of coherence-adaptive clutter filtering (CACF) designed to dynamically adapt clutter filters at each imaging pixel and frame based on local measurements of spatial coherence. In simulation studies with known scatterer and clutter motion, CACF was demonstrated to reduce velocity estimation bias while maintaining variance on par with conventional filtering.
{"title":"Spatial Coherence Adaptive Clutter Filtering in Color Flow Imaging—Part I: Simulation Studies","authors":"Will Long;David Bradway;Rifat Ahmed;James Long;Gregg E. Trahey","doi":"10.1109/OJUFFC.2022.3184914","DOIUrl":"10.1109/OJUFFC.2022.3184914","url":null,"abstract":"The appropriate selection of a clutter filter is critical for ensuring the accuracy of velocity estimates in ultrasound color flow imaging. Given the complex spatio-temporal dynamics of flow signal and clutter, however, the manual selection of filters can be a significant challenge, increasing the risk for bias and variance introduced by the removal of flow signal and/or poor clutter suppression. We propose a novel framework to adaptively select clutter filter settings based on color flow image quality feedback derived from the spatial coherence of ultrasonic backscatter. This framework seeks to relax assumptions of clutter magnitude and velocity that are traditionally required in existing adaptive filtering methods to generalize clutter filtering to a wider range of clinically-relevant color flow imaging conditions. In this study, the relationship between color flow velocity estimation error and the spatial coherence of clutter filtered channel signals was investigated in Field II simulations for a wide range of flow and clutter conditions. This relationship was leveraged in a basic implementation of coherence-adaptive clutter filtering (CACF) designed to dynamically adapt clutter filters at each imaging pixel and frame based on local measurements of spatial coherence. In simulation studies with known scatterer and clutter motion, CACF was demonstrated to reduce velocity estimation bias while maintaining variance on par with conventional filtering.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"106-118"},"PeriodicalIF":0.0,"publicationDate":"2022-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9881314/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10589914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes a new acoustic wave (AW) multiplexer topology with a single-inductor matching network for carrier aggregation (CA) in the fifth-generation communication systems. To satisfy the desired specifications of all the multiplexer ports based on ladder-type filters, the frequency response fitting method (FRFM) is proposed to obtain the BVD parameters for each AW resonator. Using the proposed computer-aided method, a parameter solution can be obtained under practical design limitations, such as the selection of the piezoelectric material, properties of the manufacturing process, and used circuit topology. Furthermore, a measurement of a band 1 and 3 surface acoustic wave (SAW) multiplexer is set up to confirm the feasibility of the proposed FRFM. The designed SAW multiplexer based on the lithium tantalate with Euler angle (0, −38, 0), 42°YX-LiTaO 3 , is arranged. The designed quadplexer achieves high selectively with a return loss (RL), stopband reflection, and isolation better than −12 dB, −43 dB, and −50 dB, respectively, in a $2.15times2.65$ mm 2 occupation. The measurement results confirm the feasibility of the multiplexer topology and the proposed FRFM. The approach is also extended to a quadplexer design with band 4 and 25 and a hexaplexer design with band 1, 3, and 7 for CA applications, demonstrating its flexibility and simplicity.
{"title":"Design for Acoustic Wave Multiplexers With Single Inductor Matching Network Using Frequency Response Fitting Method","authors":"Shu-Yuan Tseng;Min-Yuan Yang;Chin-Chung Hsiao;Yung-Yu Chen;Ruey-Beei Wu","doi":"10.1109/OJUFFC.2022.3182321","DOIUrl":"10.1109/OJUFFC.2022.3182321","url":null,"abstract":"This study proposes a new acoustic wave (AW) multiplexer topology with a single-inductor matching network for carrier aggregation (CA) in the fifth-generation communication systems. To satisfy the desired specifications of all the multiplexer ports based on ladder-type filters, the frequency response fitting method (FRFM) is proposed to obtain the BVD parameters for each AW resonator. Using the proposed computer-aided method, a parameter solution can be obtained under practical design limitations, such as the selection of the piezoelectric material, properties of the manufacturing process, and used circuit topology. Furthermore, a measurement of a band 1 and 3 surface acoustic wave (SAW) multiplexer is set up to confirm the feasibility of the proposed FRFM. The designed SAW multiplexer based on the lithium tantalate with Euler angle (0, −38, 0), 42°YX-LiTaO\u0000<sub>3</sub>\u0000, is arranged. The designed quadplexer achieves high selectively with a return loss (RL), stopband reflection, and isolation better than −12 dB, −43 dB, and −50 dB, respectively, in a \u0000<inline-formula> <tex-math>$2.15times2.65$ </tex-math></inline-formula>\u0000 mm\u0000<sup>2</sup>\u0000 occupation. The measurement results confirm the feasibility of the multiplexer topology and the proposed FRFM. The approach is also extended to a quadplexer design with band 4 and 25 and a hexaplexer design with band 1, 3, and 7 for CA applications, demonstrating its flexibility and simplicity.","PeriodicalId":73301,"journal":{"name":"IEEE open journal of ultrasonics, ferroelectrics, and frequency control","volume":"2 ","pages":"140-151"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9794779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62907340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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