scholarly journals An Integrated Front-end Circuit Board for Air-Coupled CMUT Burst-Echo Imaging

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6128
Author(s):  
Lei Ye ◽  
Jian Li ◽  
Hui Zhang ◽  
Dongmei Liang ◽  
Zhuochen Wang
Keyword(s):  
Imaging System ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Ultrasonic Transducers ◽  
Circuit Board ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Front End ◽  
Field Programmable ◽  
Good Potential ◽  
Dc Bias

To conduct burst-echo imaging with air-coupled capacitive micromachined ultrasonic transducers (CMUTs) using the same elements in transmission and reception, this work proposes a dedicated and integrated front-end circuit board design to build an imaging system. To the best of the authors’ knowledge, this is the first air-coupled CMUT burst-echo imaging using the same elements in transmission and reception. The reported front-end circuit board, controlled by field programmable gate array (FPGA), consisted of four parts: an on-board pulser, a bias-tee, a T/R switch and an amplifier. Working with our 217 kHz 16-element air-coupled CMUT array under 100 V DC bias, the front-end circuit board and imaging system could achieve 22.94 dB signal-to-noise ratio (SNR) in burst-echo imaging in air, which could represent the surface morphology and the three-dimensional form factor of the target. In addition, the burst-echo imaging range of our air-coupled CMUT imaging system, which could work between 52 and 273 mm, was discussed. This work suggests good potential for ultrasound imaging and gesture recognition applications.

scholarly journals Interferenceless Coded Aperture Correlation Holography with Point Spread Holograms of Isolated Chaotic Islands for 3D Imaging

2021 ◽  
Author(s):  
Nitin Dubey ◽  
Joseph Rosen
Keyword(s):  
3D Imaging ◽  
Imaging System ◽  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Image Sensor ◽  
Two Dimensions ◽  
Imaging Systems ◽  
Coded Aperture ◽  
Axial Resolution ◽  
Point Spread

Abstract Interferenceless coded aperture correlation holography (I-COACH) is an incoherent digital holographic technique with lateral and axial resolution similar to a regular lens-based imaging system. The properties of I-COACH are dictated by the shape of the system’s point response termed point spread hologram (PSH). As previously shown, chaotic PSHs which are continuous over some area on the image sensor enable the system to perform three-dimensional (3D) holographic imaging. We also showed that a PSH of an ensemble of sparse dots improves the system’s signal-to-noise ratio (SNR) but reduces the dimensionality of the imaging from three to two dimensions. In this study, we test the midway shape of PSH, an ensemble of sparse islands distributed over the sensor plane. A PSH of isolated chaotic islands improves the SNR of the system compared to continuous chaotic PSH without losing the capability to perform 3D imaging. Reconstructed images of this new system are compared with images of continuous PSH, dot-based PSH, and direct images of a lens-based system. Visibility, SNR, and the product of visibility with SNR are the parameters used in the study. We also demonstrate the imaging capability of a system with partial annular apertures. The reconstruction results have better SNR and visibility than lens-based imaging systems with the same annular apertures.

scholarly journals A Behavioral DC Model of 3D Distributed Diodes in Presence of Wideband Microwaves on Active Substrate Boards

2020 ◽  
Author(s):  
Pragnan Chakravorty
Keyword(s):  
Integrated Circuit ◽  
Printed Circuit Board ◽  
Three Dimensional ◽  
Circuit Board ◽  
Actual Behavior ◽  
Rf Components ◽  
Active Substrate ◽  
New Type ◽  
Dc Bias ◽  
Ic Technology

In the past few years, a new type of circuit board, named here as active substrate board (ASB), was introduced over circuit applications of diodes. Unlike a traditional printed circuit board (PCB), an ASB has its substrate made of a semiconductor. The inability of the traditional integrated circuit (IC) technology to integrate wavelength dependent radio frequency (RF) components triggered the advent of ASBs. These boards draw desirable features from IC as well as PCB technologies. Unprecedented challenges came up in modeling the different devices fabricated on an ASB owing to their large sizes and the presence of wideband microwaves. So far, modeling the effect of large sizes and ambient microwaves on DC bias of diodes have not been considered in scientific literature. Furthermore, the state of the art numerical simulators are unable to imitate the behavior of such diodes observed over measurements. Here, a semi-analytical, behavioral DC model of three dimensional (3D), distributed diodes on ASB is presented that is fairly accurate in predicting the actual behavior of the diodes. The model also opines a novel phenomenon of an AC affecting a DC with an added resistance.

Ultraminiaturized Three-Dimensional IPAC Packages With 100 μm Thick Glass Substrates for Radio Frequency Front-End Modules

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Zihan Wu ◽  
Junki Min ◽  
Vanessa Smet ◽  
Markondeya Raj Pulugurtha ◽  
Venky Sundaram ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Printed Circuit Board ◽  
Impedance Matching ◽  
Three Dimensional ◽  
Circuit Board ◽  
Electrical Performance ◽  
Active Components ◽  
Glass Substrates ◽  
Matching Networks ◽  
Front End

This paper presents innovative compact three-dimensional integrated passive and active components (3D IPAC) packages with ultrathin glass substrates for radio frequency (RF) long-term evolution (LTE) front-end modules (FEMs). High component density was achieved through double-side integration of substrate-embedded passives for impedance matching networks and three-dimensional (3D) double-side assembly of filters onto glass substrates. Glass with 100 μm thickness formed the core of the package, while four build-up layers with 15 μm thickness each were used to embed passives and form redistribution layers (RDLs). Advanced panel-scale double-side assembly processes were developed with low-cost mass reflow. Board-level assembly was realized with paste-printed solder balls and reflow on printed circuit board (PCB) with no intermediate substrates. Electrical performance of filters with substrate-embedded impedance matching networks was characterized and compared to simulations.

scholarly journals A Two-Dimensional CMUT Linear Array for Underwater Applications: Directivity Analysis and Design Optimization

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Wen Zhang ◽  
Hui Zhang ◽  
Shijiu Jin ◽  
Zhoumo Zeng
Keyword(s):  
Linear Array ◽  
Imaging System ◽  
Side Lobe ◽  
Ultrasonic Transducers ◽  
Two Dimensional ◽  
Mems Devices ◽  
Analysis And Design ◽  
Capacitive Micromachined Ultrasonic Transducers ◽  
Influential Parameters

Capacitive micromachined ultrasonic transducers (CMUTs) are one of the promising MEMS devices. This paper proposed an integrated vibration membrane structure to design a two-dimensional CMUT linear array for underwater applications. The operation frequencies for different medium have been calculated and simulated, which are 2.5 MHz in air and 0.7 MHz in water. The directivity analyses for the CMUT cell, subarray, and linear array have been provided. According to the product theorems, the directivity function of the complex array is obtained using a combination of the directivity functions of certain simple structures. Results show that the directivity of a CMUT cell is weak due to the small size, but the directivity of the designed linear array is very strong. Influential parameters of the linear array have been discussed, including the cell numbers, the adjacent distance, and the operation medium. In order to further suppress the side lobe interference and improve the resolution and the imaging quality of the imaging system, several weighting methods are used for optimization and comparison. Satisfactory side lobe suppression results are obtained, which can meet the actual requirements.

Some Quantification Problems in Parallel EELS Images

1990 ◽  
Vol 48 (2) ◽  
pp. 36-37
Author(s):  
G. Botton ◽  
G. L’Espérance ◽  
M.D. Ball ◽  
C.E. Gallerneault
Keyword(s):  
Electron Microscope ◽  
Imaging System ◽  
Signal To Noise Ratio ◽  
Scanning Transmission Electron Microscope ◽  
Acquisition Time ◽  
Thickness Variation ◽  
Transmission Electron ◽  
Distribution Of Elements ◽  
Scanning Transmission ◽  
Present Distribution

The recently developed parallel electron energy loss spectrometers (PEELS) have led to a significant reduction in spectrum acquisition time making EELS more useful in many applications in material science. Dwell times as short as 50 msec per spectrum with a PEELS coupled to a scanning transmission electron microscope (STEM), can make quantitative EEL images accessible. These images would present distribution of elements with the high spatial resolution inherent to EELS. The aim of this paper is to briefly investigate the effect of acquisition time per pixel on the signal to noise ratio (SNR), the effect of thickness variation and crystallography and finally the energy stability of spectra when acquired in the scanning mode during long periods of time.The configuration of the imaging system is the following: a Gatan PEELS is coupled to a CM30 (TEM/STEM) electron microscope, the control of the spectrometer and microscope is performed through a LINK AN10-85S MCA which is interfaced to a IBM RT 125 (running under AIX) via a DR11W line.

Cryomicroscopy of crotoxin complex crystals at 400 KV

1989 ◽  
Vol 47 ◽  
pp. 826-827
Author(s):  
Jaap Brink ◽  
Wah Chiu
Keyword(s):  
Signal To Noise Ratio ◽  
3D Structure ◽  
Three Dimensional ◽  
Carbon Films ◽  
Depth Of Field ◽  
Basic Subunit ◽  
Ewald Sphere ◽  
Diffraction Patterns ◽  
Complex Crystals ◽  
Acidic Subunit

The crotoxin complex is a potent neurotoxin composed of a basic subunit (Mr = 12,000) and an acidic subunit (M = 10,000). The basic subunit possesses phospholipase activity whereas the acidic subunit shows no enzymatic activity at all. The complex's toxocity is expressed both pre- and post-synaptically. The crotoxin complex forms thin crystals suitable for electron crystallography. The crystals diffract up to 0.16 nm in the microscope, whereas images show reflections out to 0.39 nm2. Ultimate goal in this study is to obtain a three-dimensional (3D-) structure map of the protein around 0.3 nm resolution. Use of 100 keV electrons in this is limited; the unit cell's height c of 25.6 nm causes problems associated with multiple scattering, radiation damage, limited depth of field and a more pronounced Ewald sphere curvature. In general, they lead to projections of the unit cell, which at the desired resolution, cannot be interpreted following the weak-phase approximation. Circumventing this problem is possible through the use of 400 keV electrons. Although the overall contrast is lowered due to a smaller scattering cross-section, the signal-to-noise ratio of especially higher order reflections will improve due to a smaller contribution of inelastic scattering. We report here our preliminary results demonstrating the feasability of the data collection procedure at 400 kV.Crystals of crotoxin complex were prepared on carbon-covered holey-carbon films, quench frozen in liquid ethane, inserted into a Gatan 626 holder, transferred into a JEOL 4000EX electron microscope equipped with a pair of anticontaminators operating at −184°C and examined under low-dose conditions. Selected area electron diffraction patterns (EDP's) and images of the crystals were recorded at 400 kV and −167°C with dose levels of 5 and 9.5 electrons/Å, respectively.

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