@article{chen_kim_zhang_yang_osada_crosby_lyerly_jiang_2022, title={Intracorporeal Sonoporation-Induced Drug/Gene Delivery Using a Catheter Ultrasound Transducer}, ISSN={["1948-5719"]}, DOI={10.1109/IUS54386.2022.9958222}, abstractNote={Ultrasound (US) has been recently demonstrated promising in cancer immunotherapy. By virtue of microbubble-mediated cavitation, US can induce temporary pores in the cell membrane to enhance drug/gene delivery and this process is termed sonoporation. Currently, the typical US transducer for sonoporation is extracorporeal, lacking the ability to target lesions behind bones and fat efficiently, as well as to inject microbubbles (MBs) and nucleic acids into the US treatment zone simultaneously. These issues can decrease the drug/gene delivery effectiveness and increase the undesired systemic toxicity for cancer immunotherapy. Here we demonstrated an 800 kHz miniaturized US transducer for intracorporeal sonoporation-induced drug/gene delivery. Acoustic simulation using k-Wave toolbox was carried out to explore the 800 kHz US wave propagation in a 384-well cell culture plate. In-vitro sonoporation tests using human embryonic kidney (HEK) 293T cells and green fluorescent protein-luciferase (GFP-LUC) encoded plasmid DNA were conducted with various sonication parameters (i.e., 0.1 – 0.7 MPa peak-negative pressure; 20 – 2000 cycle number). The LUC assay demonstrated a significantly enhanced transfection, indicating the developed catheter transducer is promising for intracorporeal sonoporation-induced drug/gene delivery, such as intratumoral immunotherapy.}, journal={2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)}, author={Chen, Mengyue and Kim, Howuk and Zhang, Bohua and Yang, Waston and Osada, Takuya and Crosby, Erika J. and Lyerly, H. Kim and Jiang, Xiaoning}, year={2022} }
 @article{chen_zhang_kim_sheng_chen_kim_geng_jiang_2022, title={Millisecond-Level Transient Temperature Monitoring Using an Ultra-Fast Response Thermocouple for Ultrasound-Induced Thermal Strain Imaging}, ISSN={["1948-5719"]}, DOI={10.1109/IUS54386.2022.9958761}, journal={2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)}, author={Chen, Mengyue and Zhang, Bohua and Kim, Howuk and Sheng, Zhiyu and Chen, Qiyang and Kim, Kang and Geng, Xuecang and Jiang, Xiaoning}, year={2022} }
 @article{chen_peng_wu_huang_kim_traylor_muller_chhatbar_nam_feng_et al._2022, title={Numerical and experimental evaluation of low-intensity transcranial focused ultrasound wave propagation using human skulls for brain neuromodulation}, volume={11}, ISSN={["2473-4209"]}, DOI={10.1002/mp.16090}, abstractNote={Low-intensity transcranial focused ultrasound (tFUS) has gained considerable attention as a promising noninvasive neuromodulatory technique for human brains. However, the complex morphology of the skull hinders scholars from precisely predicting the acoustic energy transmitted and the region of the brain impacted during the sonication. This is due to the fact that different ultrasound frequencies and skull morphology variations greatly affect wave propagation through the skull.Although the acoustic properties of human skull have been studied for tFUS applications, such as tumor ablation using a multielement phased array, there is no consensus about how to choose a single-element focused ultrasound (FUS) transducer with a suitable frequency for neuromodulation. There are interests in exploring the magnitude and dimension of tFUS beam through human parietal bone for modulating specific brain lobes. Herein, we aim to investigate the wave propagation of tFUS on human skulls to understand and address the concerns above.Both experimental measurements and numerical modeling were conducted to investigate the transmission efficiency and beam pattern of tFUS on five human skulls (C3 and C4 regions) using single-element FUS transducers with six different frequencies (150-1500 kHz). The degassed skull was placed in a water tank, and a calibrated hydrophone was utilized to measure acoustic pressure past it. The cranial computed tomography scan data of each skull were obtained to derive a high-resolution acoustic model (grid point spacing: 0.25 mm) in simulations. Meanwhile, we modified the power-law exponent of acoustic attenuation coefficient to validate numerical modeling and enabled it to be served as a prediction tool, based on the experimental measurements.The transmission efficiency and -6 dB beamwidth were evaluated and compared for various frequencies. An exponential decrease in transmission efficiency and a logarithmic decrease of -6 dB beamwidth with an increase in ultrasound frequency were observed. It is found that a >750 kHz ultrasound leads to a relatively lower tFUS transmission efficiency (<5%), whereas a <350 kHz ultrasound contributes to a relatively broader beamwidth (>5 mm). Based on these observations, we further analyzed the dependence of tFUS wave propagation on FUS transducer aperture size.We successfully studied tFUS wave propagation through human skulls at different frequencies experimentally and numerically. The findings have important implications to predict tFUS wave propagation for ultrasound neuromodulation in clinical applications, and guide researchers to develop advanced ultrasound transducers as neural interfaces.}, journal={MEDICAL PHYSICS}, author={Chen, Mengyue and Peng, Chang and Wu, Huaiyu and Huang, Chih-Chung and Kim, Taewon and Traylor, Zachary and Muller, Marie and Chhatbar, Pratik Y. and Nam, Chang S. and Feng, Wuwei and et al.}, year={2022}, month={Nov} }
 @misc{peng_cai_chen_jiang_2022, title={Recent Advances in Tracking Devices for Biomedical Ultrasound Imaging Applications}, volume={13}, ISSN={["2072-666X"]}, DOI={10.3390/mi13111855}, abstractNote={With the rapid advancement of tracking technologies, the applications of tracking systems in ultrasound imaging have expanded across a wide range of fields. In this review article, we discuss the basic tracking principles, system components, performance analyses, as well as the main sources of error for popular tracking technologies that are utilized in ultrasound imaging. In light of the growing demand for object tracking, this article explores both the potential and challenges associated with different tracking technologies applied to various ultrasound imaging applications, including freehand 3D ultrasound imaging, ultrasound image fusion, ultrasound-guided intervention and treatment. Recent development in tracking technology has led to increased accuracy and intuitiveness of ultrasound imaging and navigation with less reliance on operator skills, thereby benefiting the medical diagnosis and treatment. Although commercially available tracking systems are capable of achieving sub-millimeter resolution for positional tracking and sub-degree resolution for orientational tracking, such systems are subject to a number of disadvantages, including high costs and time-consuming calibration procedures. While some emerging tracking technologies are still in the research stage, their potentials have been demonstrated in terms of the compactness, light weight, and easy integration with existing standard or portable ultrasound machines.}, number={11}, journal={MICROMACHINES}, author={Peng, Chang and Cai, Qianqian and Chen, Mengyue and Jiang, Xiaoning}, year={2022}, month={Nov} }
 @misc{peng_chen_spicer_jiang_2021, title={Acoustics at the nanoscale (nanoacoustics): A comprehensive literature review. Part I: Materials, devices and selected applications}, volume={332}, ISSN={["1873-3069"]}, DOI={10.1016/j.sna.2021.112719}, abstractNote={In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the last decade, for the first time, recent advancements of acoustics-associated nanomaterials/nanostructures and nanodevices for different applications are outlined in this comprehensive review, which is written in two parts. As part I of this two part review, firstly, active and passive nanomaterials and nanostructures for acoustics are presented. Following that, representative applications of nanoacoustics including material property characterization, nanomaterial/nanostructure manipulation, and sensing, are discussed in detail. Finally, a summary is presented with point of views on the current challenges and potential solutions in this burgeoning field.}, journal={SENSORS AND ACTUATORS A-PHYSICAL}, author={Peng, Chang and Chen, Mengyue and Spicer, James B. and Jiang, Xiaoning}, year={2021}, month={Dec} }
 @misc{peng_chen_spicer_jiang_2021, title={Acoustics at the nanoscale (nanoacoustics): A comprehensive literature review. Part II: Nanoacoustics for biomedical imaging and therapy}, volume={332}, ISSN={["1873-3069"]}, DOI={10.1016/j.sna.2021.112925}, abstractNote={In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the last decade, for the first time, recent advancements of acoustics-associated nanomaterials/nanostructures and nanodevices for different applications are outlined in this comprehensive review, which is written in two parts. As part II of this two-part review, this paper concentrates on nanoacoustics in biomedical imaging and therapy applications, including molecular ultrasound imaging, photoacoustic imaging, ultrasound-mediated drug delivery and therapy, and photoacoustic drug delivery and therapy. Firstly, the recent developments of nanosized ultrasound and photoacoustic contrast agents as well as their various imaging applications are examined. Secondly, different types of nanomaterials/nanostructures as nanocarriers for ultrasound and photoacoustic therapies are discussed. Finally, a discussion of challenges and future research directions are provided for nanoacoustics in medical imaging and therapy.}, journal={SENSORS AND ACTUATORS A-PHYSICAL}, author={Peng, Chang and Chen, Mengyue and Spicer, James B. and Jiang, Xiaoning}, year={2021}, month={Dec} }
 @article{chen_peng_kim_chhatbar_muller_feng_jiang_2021, title={Biosafety of Low-Intensity Pulsed Transcranial Focused Ultrasound Brain Stimulation - A Human Skull Study}, volume={11593}, ISSN={["1996-756X"]}, DOI={10.1117/12.2582487}, abstractNote={Among a variety of existing modalities for noninvasive brain stimulation (NIBS), low-intensity pulsed transcranial focused ultrasound (tFUS) is a promising technique to precisely stimulate deep brain structures due to its high spatial specificity and superior penetration depth. While tFUS is gaining momentum as an emerging NIBS technique, an advisable biosafety-associated combination of sonication parameters including duty cycle and power input remains to be explored. In this study, biosafety of low-intensity pulsed tFUS using various sonication parameters was evaluated by measuring acoustic intensities and temperature variations across a piece of real human skull. The results showed that ISPTA above 480 mW/cm^2 is likely to induce an excessive temperature rise for a sonication duration of 160 seconds. Also, the skull base effect and ultrasound transducer self-heating effect should be noted during the sonication. Based on the findings in this study, an initial biosafety guide was discussed for the future investigation of ultrasound-mediated NIBS.}, journal={HEALTH MONITORING OF STRUCTURAL AND BIOLOGICAL SYSTEMS XV}, author={Chen, Mengyue and Peng, Chang and Kim, Taewon and Chhatbar, Pratik Y. and Muller, Marie and Feng, Wuwei and Jiang, Xiaoning}, year={2021} }
 @article{peng_chen_wang_shen_jiang_2021, title={Broadband Piezoelectric Transducers for Under-Display Ultrasonic Fingerprint Sensing Applications}, volume={68}, ISSN={["1557-9948"]}, DOI={10.1109/TIE.2020.2984977}, abstractNote={Smartphones today have attracted a continuous trend of pursuing narrow-bezel and full-screen displays. To allow for a more user-friendly front side fingerprint recognition in full-screen displays, it is crucial to develop an under-display type of fingerprint sensor. Among fingerprint sensing techniques, ultrasonic fingerprint sensing has been proved to be able to provide more distinctive features and give a high resistance to spoof attacks. However, until now no study about under-display ultrasonic fingerprint sensing has been reported. In this article, for the first time, multilayer under-display ultrasonic fingerprint sensor structure using various active materials/structures were theoretically designed and compared. Based on the theoretical analysis results, a lead zirconate titanate (PZT)-5A-based multilayer under-display ultrasonic fingerprint sensor with a resonant frequency of 20 MHz, and a −6-dB fractional bandwidth of more than 70% was fabricated to meet the requirements of resolution and sensitivity for the under-display ultrasonic fingerprint imaging applications. The prototyped sensor was characterized, and the fingerprint recognition capability was tested using a custom-made fingerprint-mimicking phantom. The phantom images were acquired based on the pulse-echo imaging method. With the 1 μJ impulse driving signal, the sensor was manipulated to image a 2.0 mm × 1.0 mm section of fingerprint-mimicking phantom by mechanical scanning, obtaining an electronic image with 500 × 500 DPI. The fingerprint-mimicking phantom imaging results suggest that the 20 MHz broadband PZT-based multilayer structure holds great potential for under-display ultrasonic fingerprint sensor applications.}, number={5}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Peng, Chang and Chen, Mengyue and Wang, Hongchao and Shen, Jian and Jiang, Xiaoning}, year={2021}, month={May}, pages={4426–4434} }
 @article{chen_sheng_kim_zhang_chen_kim_geng_jiang_2021, title={Design and Simulation of Heating Transducer Arrays for Ultrasound-Induced Thermal Strain Imaging}, ISSN={["1948-5719"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85122893882&partnerID=MN8TOARS}, DOI={10.1109/IUS52206.2021.9593531}, abstractNote={Ultrasound-induced thermal strain imaging (US-TSI) has been proposed as an effective diagnostic modality for atherosclerosis plaque detection. The main challenge of current US-TSI for human subjects is the demand for a very fast temperature rise in a relatively large volume, with appropriate acoustic power that is under the Food and Drug Administration (FDA) safety limit, to cover a major artery such as carotid, and to avoid any physiologic motion artifacts. Therefore, we aim to develop heating transducer arrays with satisfied capabilities in terms of heating volume and speed for US-TSI. By virtue of using symmetrical 3.5 MHz dual 1.5D arrays and applying the dual-focus beamforming approach, the acoustic and thermal simulation results demonstrated that the designed dual heating arrays can induce a 2.1 °C temperature rise within 50 ms in a volume of 2 × 10 × 10 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> (in terms of full width at half maximum, FWHM). The transmitting sensitivity and power conversion efficiency for a single element was estimated to be 14.1 kPa/V and 72.43%, respectively. It showed that the designed dual 1.5D heating transducer arrays can be promising for US-TSI applications.}, journal={INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS 2021)}, author={Chen, Mengyue and Sheng, Zhiyu and Kim, Howuk and Zhang, Bohua and Chen, Qiyang and Kim, Kang and Geng, Xuecang and Jiang, Xiaoning}, year={2021} }
 @misc{nam_traylor_chen_jiang_feng_chhatbar_2021, title={Direct Communication Between Brains: A Systematic PRISMA Review of Brain-To-Brain Interface}, volume={15}, ISSN={["1662-5218"]}, url={http://dx.doi.org/10.3389/fnbot.2021.656943}, DOI={10.3389/fnbot.2021.656943}, abstractNote={This paper aims to review the current state of brain-to-brain interface (B2BI) technology and its potential. B2BIs function via a brain-computer interface (BCI) to read a sender's brain activity and a computer-brain interface (CBI) to write a pattern to a receiving brain, transmitting information. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to systematically review current literature related to B2BI, resulting in 15 relevant publications. Experimental papers primarily used transcranial magnetic stimulation (tMS) for the CBI portion of their B2BI. Most targeted the visual cortex to produce phosphenes. In terms of study design, 73.3% (11) are unidirectional and 86.7% (13) use only a 1:1 collaboration model (subject to subject). Limitations are apparent, as the CBI method varied greatly between studies indicating no agreed upon neurostimulatory method for transmitting information. Furthermore, only 12.4% (2) studies are more complicated than a 1:1 model and few researchers studied direct bidirectional B2BI. These studies show B2BI can offer advances in human communication and collaboration, but more design and experiments are needed to prove potential. B2BIs may allow rehabilitation therapists to pass information mentally, activating a patient's brain to aid in stroke recovery and adding more complex bidirectionality may allow for increased behavioral synchronization between users. The field is very young, but applications of B2BI technology to neuroergonomics and human factors engineering clearly warrant more research.}, journal={FRONTIERS IN NEUROROBOTICS}, publisher={Frontiers Media SA}, author={Nam, Chang S. and Traylor, Zachary and Chen, Mengyue and Jiang, Xiaoning and Feng, Wuwei and Chhatbar, Pratik Yashvant}, year={2021}, month={May} }
 @misc{kim_park_chhatbar_feld_mac grory_nam_wang_chen_jiang_feng_2021, title={Effect of Low Intensity Transcranial Ultrasound Stimulation on Neuromodulation in Animals and Humans: An Updated Systematic Review}, volume={15}, ISSN={["1662-453X"]}, DOI={10.3389/fnins.2021.620863}, abstractNote={Background: Although low-intensity transcranial ultrasound stimulation (LI-TUS) has received more recognition for its neuromodulation potential, there remains a crucial knowledge gap regarding the neuromodulatory effects of LI-TUS and its potential for translation as a therapeutic tool in humans. Objective: In this review, we summarized the findings reported by recently published studies regarding the effect of LI-TUS on neuromodulation in both animals and humans. We also aim to identify challenges and opportunities for the translation process. Methods: A literature search of PubMed, Medline, EMBASE, and Web of Science was performed from January 2019 to June 2020 with the following keywords and Boolean operators: [transcranial ultrasound OR transcranial focused ultrasound OR ultrasound stimulation] AND [neuromodulation]. The methodological quality of the animal studies was assessed by the SYRCLE's risk of bias tool, and the quality of human studies was evaluated by the PEDro score and the NIH quality assessment tool. Results: After applying the inclusion and exclusion criteria, a total of 26 manuscripts (24 animal studies and two human studies) out of 508 reports were included in this systematic review. Although both inhibitory (10 studies) and excitatory (16 studies) effects of LI-TUS were observed in animal studies, only inhibitory effects have been reported in primates (five studies) and human subjects (two studies). The ultrasonic parameters used in animal and human studies are different. The SYRCLE quality score ranged from 25 to 43%, with a majority of the low scores related to performance and detection bias. The two human studies received high PEDro scores (9/10). Conclusion: LI-TUS appears to be capable of targeting both superficial and deep cerebral structures to modulate cognitive or motor behavior in both animals and humans. Further human studies are needed to more precisely define the effective modulation parameters and thereby translate this brain modulatory tool into the clinic.}, journal={FRONTIERS IN NEUROSCIENCE}, author={Kim, Taewon and Park, Christine and Chhatbar, Pratik Y. and Feld, Jody and Mac Grory, Brian and Nam, Chang S. and Wang, Pu and Chen, Mengyue and Jiang, Xiaoning and Feng, Wuwei}, year={2021}, month={Apr} }
 @article{park_chen_kim_2021, title={Implication of auditory confounding in interpreting somatosensory and motor responses in low-intensity focused transcranial ultrasound stimulation}, volume={125}, ISSN={["1522-1598"]}, DOI={10.1152/jn.00701.2020}, abstractNote={Low-intensity transcranial focused ultrasound (LI-tFUS) stimulation is a noninvasive neuromodulation tool that demonstrates high target localization accuracy and depth penetration. It has been shown to modulate activities in the primary motor and somatosensory cortex. Previous studies in animals as well as in humans, illustrated in the recently published paper in Brain Stimulation by Braun et al. [Braun V, Blackmore J, Cleveland RO, Butler CR. Brain Stimul 13: 1527-1534, 2020], acknowledged the possibility of indirect stimulation of the peripheral auditory pathway that could confound the somatosensory and motor responses observed with LI-tFUS stimulation. Here, we discuss the implications and interpretations of auditory confounding in the context of neuromodulation.}, number={6}, journal={JOURNAL OF NEUROPHYSIOLOGY}, author={Park, Christine and Chen, Mengyue and Kim, Taewon}, year={2021}, month={Jun}, pages={2356–2360} }
 @article{peng_chen_sim_zhu_jiang_2021, title={Noninvasive and Nonocclusive Blood Pressure Monitoring via a Flexible Piezo-Composite Ultrasonic Sensor}, volume={21}, ISSN={["1558-1748"]}, DOI={10.1109/JSEN.2020.3021923}, abstractNote={Continuous blood pressure monitoring in everyday life is important and necessary to detect and control high blood pressure in advance. While the existing blood pressure monitoring techniques are well suited for applications in current clinical settings, they are inadequate for next-generation wearable long-term monitoring of blood pressure on a daily basis. In this study, a flexible piezo-composite ultrasonic sensor was reported, for the first time, for continuous blood pressure measurement through ultrasonic motion tracking of blood vessel wall. A flexible piezo-composite ultrasonic sensor was designed and fabricated with a layer of PZT-5A/ polydimethylsiloxane (PDMS) anisotropic 1-3 composite and silver nanowire based stretchable electrodes. The material properties and dimensions of the sensor were determined according to the volume fraction of PZT-5A and the material properties of PZT-5A and PDMS. The experimental results illustrated that the flexible sensor possessed adequate bandwidth and sensitivity for blood pressure monitoring. Continuous blood pressure measurement was successfully conducted with the ulnar artery on a volunteer's right arm. Compared with the measurement results using a clinical ultrasound probe and a commercial upper arm blood monitor, the results obtained in this study demonstrated the capability of the proposed flexible sensor to continuously monitor blood pressure waveforms during cardiac cycles. The flexible sensor provides a promising solution for noninvasive, nonocclusive and calibration-free blood pressure monitoring. It has great potential to be integrated into a wearable ultrasonic healthcare sensing system for blood pressure and flow monitoring.}, number={3}, journal={IEEE SENSORS JOURNAL}, author={Peng, Chang and Chen, Mengyue and Sim, Hun Ki and Zhu, Yong and Jiang, Xiaoning}, year={2021}, month={Feb}, pages={2642–2650} }
 @article{peng_chen_jiang_2021, title={Under-Display Ultrasonic Fingerprint Recognition With Finger Vessel Imaging}, volume={21}, ISSN={["1558-1748"]}, DOI={10.1109/JSEN.2021.3051975}, abstractNote={While fingerprint technology has been widely used in mobile devices for user identification, the existing fingerprint sensors can only capture 2D images of the fingerprint and are thus vulnerable to spoofing attacks using 2D replicas of fingerprint. Ultrasonic fingerprint recognition via imaging the structures beneath the human skin can be a promising approach for preventing spoofing attacks on fingerprint-based identification devices. In this study, under-display ultrasonic fingerprint recognition (UDUFR) was investigated for the first time via imaging a finger vessel underneath the fingerprint. A 40 MHz ultrasonic fingerprint sensor composed of PZT-5H piezoelectric active material was firstly developed, which demonstrated broad bandwidth (73.9%) and high loop sensitivity (−27.5 dB) for UDUFR applications. UDUFR experiments were performed to demonstrate the effectiveness of the proposed technique using a two-layer polydimethylsiloxane (PDMS) phantom which consists of a dummy fingerprint in the surface layer and a finger vessel mimicker in the inner layer. Electronic images of the fingerprint and finger vessel with a resolution of $500\times500$ DPI were successfully obtained. The results reported in this study open up new avenues for the next generation of robust and secure UDUFR technology.}, number={6}, journal={IEEE SENSORS JOURNAL}, author={Peng, Chang and Chen, Mengyue and Jiang, Xiaoning}, year={2021}, month={Mar}, pages={7412–7419} }
 @article{peng_chen_wang_shen_jiang_2020, title={P(VDF-TrFE) Thin-Film-Based Transducer for Under-Display Ultrasonic Fingerprint Sensing Applications}, volume={20}, ISSN={["1558-1748"]}, DOI={10.1109/JSEN.2020.2997375}, abstractNote={The use of fingerprint for biometric identification is one of the most prevalent authentication methods applied today in smartphones. In the course of pursuing narrow-bezel and full-screen display, the under-display fingerprint sensor is considered to be a user-friendly and practical solution for newer models of smartphone. While under-display optical fingerprint sensor has been commercially available in various smartphones, it demonstrates limitations such as sensitivity to humidity and contaminations including oil and water as well as easy to spoof. Ultrasonic fingerprint sensing has been proved to be able to overcome these limitations. In this study, P(VDF-TrFE) piezoelectric polymer-based transducer was reported, for the first time, for under-display ultrasonic fingerprint sensing applications. In specific, a 40 MHz ultrasonic transducer using a layer of $10~\mu \text{m}$ thick P(VDF-TrFE) thin-film was designed, fabricated, and characterized. The under-display ultrasonic fingerprint sensing capability of the prototyped transducer was experimentally validated using phantoms of real fingerprint. Electronic images of fingerprint with resolution of $500\times500$ DPI were obtained through under-display ultrasonic fingerprint sensing tests. The lateral resolution of the transducer was calculated to be $\sim ~70~\mu \text{m}$ . The results of this study illustrate promising advances in under-display ultrasonic fingerprint sensing applications.}, number={19}, journal={IEEE SENSORS JOURNAL}, author={Peng, Chang and Chen, Mengyue and Wang, Hongchao and Shen, Jian and Jiang, Xiaoning}, year={2020}, month={Oct}, pages={11221–11228} }