Juneho Hwang’s research while affiliated with Cornell University and other places

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Publications (6)


Sonic Fourier Transform Imaging Using GHz Ultrasonic Transducer Array
  • Conference Paper

January 2024

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3 Reads

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2 Citations

Juneho Hwang

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Fig. 1. The Geegah Imager has 128x128 50μm transmit/receive AlN transducers. The total size of the ultrasonic imager is 6.4x6.4mm. Different 0.9mm diameter lens designs were tested with the imager [4], [18].
Fig. 2. The lens can have two different designs. (a) is a concave lens that diverges the wave. (b) is a convex lens that converges the wave. It shows a schematic picture of the curved, Fresnel, and meta lens and the optical image of the fabricated lens.
Fig. 3. The ultrasonic lens consists of SiO2 posts embedded on top of the wafer. The spatial distribution of the posts represents the different heights of the Fresnel lens.
Fig. 4. The acoustic pressure reflected from the lens is plotted at different frequencies. The acoustic wave reflects from the lens and reaches the transmitter after 0.13μs. (c) and (d) show the cross-section of the pressure wave from the first and second maximum in front of the transmitter.
Fig. 5. Acoustic pressure is plotted for the reflected wave from the lens. The convex lens has a higher focusing effect compared to the concave lens.

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Gigahertz Metamaterial Ultrasonic Lens Characterization Using GHz CMOS Integrated Ultrasonic Micro Imager
  • Conference Paper
  • Full-text available

October 2022

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216 Reads

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4 Citations

Juneho Hwang

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In-situ ultrasonic imaging of printed electronics ink deposition and curing

We report the first-ever in-situ imaging of 3D-Printed Electronics (PE) ink delivery and drying during the printing using GHz ultrasonic imager. The CMOS integrated GHz ultrasonic technology consists of a 128 x 128-pixel array of Aluminum Nitride transducers that image the surface of the silicon chip with transmit/receive of short ultrasonic pulses. The reflected US pulses measure crucial ink parameters such as ink's acoustic impedance and temperature at a sampling rate of up to 30 frames per second. We demonstrate the observation of ink droplets delivered to a surface, the creation of secondary droplets on the surface, and the time history of the ink curing process. The data at single pixel and images over a collection of images indicates that the GHz imager can be used to provide real-time quantitative feedback on the printing process, thus providing uniform and higher yield PE devices.




Citations (5)


... Existen diferentes técnicas para procesamiento de señales digitalizadas del sonido. Una de las más usadas es la trasformada de Fourier (Wang, Chen, Shen, Zhong, & Li, 2022), (Hwang, Kuo, Baskota, & Lal, 2024), (Konno, Dobroiu, Suzuki, Asada, & Ito, 2021), (Zhou & Lu, 2021). ...

Reference:

Análisis de frecuencias de resonancia en jitomates para determinar su estado de maduración.
Sonic Fourier Transform Imaging Using GHz Ultrasonic Transducer Array
  • Citing Conference Paper
  • January 2024

... However, the spatial resolution (0.5 -2mm) provided by this frequency range is insufficient for smaller organisms to capture their fine structural details. On the other hand, GHz frequencies offer significantly higher resolution of ∼0.5 m to 50 , which have been previously used to study cells [9], [10], soil nematodes [11], thin chitosan films [12], and metamaterial lenses [13]. Therefore, GHz Ultrasonic Imaging has the potential to resolve mechanical properties of C. elegans at a higher resolution. ...

Gigahertz Metamaterial Ultrasonic Lens Characterization Using GHz CMOS Integrated Ultrasonic Micro Imager

... Due to their powerful parallel processing, high computational efficiency, and minimal crosstalk, wave-based analog computing systems have been hailed as a potential future of computing 1,8,9 . It was the pioneering work of Silva et al. 10 on computational metamaterials that set the stage for subsequent research into analog computing systems that perform mathematical operations and solve equations [1][2][3][4]37 , with a subset of these focusing on the use of the Fourier transform (FT) to do so 3,6,9,10,[26][27][28]37 . More recently, Zangeneh-Nejad et al. provided a well-written, comprehensive overview of recent developments in this field as a whole 1 . ...

Focusing Profiles of Planar Si-SiO 2 Metamaterial GHz Frequency Ultrasonic Lens
  • Citing Conference Paper
  • September 2021

... The Fourier transform (FT) is a mathematical operation that maps a function in one variable to the spectral space of its conjugate variable 14,36-38 . It is a powerful tool with wide-ranging applications in myriad disciplines 4,[22][23][24][36][37][38][39][40][41][42][43] . Currently, the two-dimensional Fast Fourier Transform (FFT) algorithm has a computational complexity of O (N 2 logN) , which is not efficient enough for certain applications, such as real-time image processing in autonomous systems 4,22-24 . ...

Planar Lens for GHz Fourier Ultrasonics
  • Citing Conference Paper
  • September 2020

... To date, the ultrasonic WFC has been investigated only for the FFT of 2D data for image processing, however, 1-D FFT for signal processing is important and how to use such a WFC system for signal processing remains unknown. On the other hand, the WFC system using GHz ultrasonic waves 11,13,14 passing through a flat lens 15,16 will be finally packaged into a chip by semiconductor technologies. Before fabrication and measurement, it is important to validate the idea, investigate the main factors that which cause errors, and optimize the system design. ...

Planar GHz Ultrasonic Lens for Fourier Ultrasonics
  • Citing Conference Paper
  • October 2019