scholarly journals An Improved Equivalent Circuit Simulation of High Frequency Ultrasound Transducer

2021 ◽  
Vol 8 ◽  
Author(s):  
Zhitian Shen ◽  
Jie Xu ◽  
Zhangjian Li ◽  
Youwei Chen ◽  
Yaoyao Cui ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
High Frequency ◽  
Circuit Simulation ◽  
Simulation Software ◽  
Ultrasound Transducer ◽  
Ultrasound Transducers ◽  
High Frequency Ultrasound ◽  
Matching Layer ◽  
Backing Layer ◽  
Frequency Ultrasound

The equivalent circuit simulation plays an important role in the design of ultrasound transducer. However, the existing methods are difficult to achieve the effect of matching and backing layer, and not able to accurately simulate the transducer with cable. Especially in the application of high frequency ultrasound, the long cable has a great influence on the performance of the transducer. To overcome these limitations, this paper proposed an improved equivalent circuit method, which combined Leach model and transmission line model. It can realize the complete simulation of ultrasound transducer with a long cable, matching layer, and backing layer in PSPICE circuit simulation software when the parameters were measured. Its principles were briefly introduced, and ultrasound transducers with different frequencies (12 and 20 MHz), different matching layers, and different cable lengths (0.5–2.5 m) were designed and fabricated to verify the effectiveness of the method, which is also compared with the traditional KLM method using PiezoCAD. The experiment results showed that the long cable, matching layer, and backing layer have a significant impact on the performance of high frequency ultrasound transducers, and this proposed method has good agreement with these results. Moreover, for the simulation of the complete transducer, the effect of this method is better than KLM model. Besides, this method does not need to know the specific equivalent circuit of matching, backing layer, or cable wire, it can accurately predict the impedance and phase of the transducer through the material parameters, which is very helpful for the material selection and optimization of subsequent transducer design and fabrication. The study indicates that this improved equivalent circuit method is suitable to be applied in the general circuit simulation software and provides strong support for the high frequency transducer and system design.

scholarly journals ZnO thin-film optimization towards the fabrication of high-frequency ultrasound transducers

2021 ◽  
Author(s):  
◽  
Ihab Sinno
Keyword(s):  
Zinc Oxide ◽  
High Frequency ◽  
Oxide Films ◽  
Single Element ◽  
High Deposition Rate ◽  
Ultrasound Transducers ◽  
Metal Contacts ◽  
High Frequency Ultrasound ◽  
Zinc Oxide Films ◽  
Frequency Ultrasound

<p>Zinc oxide is a popular wide bandgap semiconductor material with versatile electrical and optical properties. In its wurtzite crystal form, this semiconductor is piezoelectric, and has material properties that make it an attractive candidate for fabricating high frequency ultrasound transducers. This thesis describes the development of an RF sputtering process for creating zinc oxide films with thicknesses ranging from 3μm to 10μm, aiming for transducer frequencies of 300MHz to 1 GHz. Sputtering parameters are optimized to meet the dual requirements of a c-axis film orientation while maintaining a high deposition rate. These constraints and the dimensional characteristics of the utilized sputtering system, such as the short substrate-to-target distance, introduce high levels of strain in the deposited zinc oxide films. Various anneal procedures are developed to reduce film strain and optimize the resulting microstructure. It is found that annealing temperatures > 600°C eliminate the inherent film strain, but simultaneously result in the dewetting of the bottom metal contact, making this thermal treatment unsuitable for device processing. As an alternative to traditional metal contacts used in ultrasound transducers, the use of highly doped zinc oxide contacts is then investigated. It is shown that aluminium doped zinc oxide contacts provide an improved seed layer for device growth while eliminating the dewetting problems associated with metal contacts at high anneal temperatures. In addition, the use of such transparent conductive oxide contacts can lead to novel ultrasound applications, which benefit from the integration of optical and acoustic imaging in a single lens. A proof of concept all-zinc oxide single element ultrasound transducer structure is finally fabricated, to highlight the potential of an integrated optical-acoustic lens design.</p>

scholarly journals A Wideband Noise and Harmonic Distortion Canceling Low-Noise Amplifier for High-Frequency Ultrasound Transducers

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8476
Author(s):  
Yuxuan Tang ◽  
Yulang Feng ◽  
He Hu ◽  
Cheng Fang ◽  
Hao Deng ◽  
...  
Keyword(s):  
High Frequency ◽  
Harmonic Distortion ◽  
Low Noise ◽  
Low Noise Amplifier ◽  
Cmos Process ◽  
Ultrasound Transducers ◽  
High Frequency Ultrasound ◽  
Front End ◽  
Noise Amplifier ◽  
Frequency Ultrasound

This paper presents a wideband low-noise amplifier (LNA) front-end with noise and distortion cancellation for high-frequency ultrasound transducers. The LNA employs a resistive shunt-feedback structure with a feedforward noise-canceling technique to accomplish both wideband impedance matching and low noise performance. A complementary CMOS topology was also developed to cancel out the second-order harmonic distortion and enhance the amplifier linearity. A high-frequency ultrasound (HFUS) and photoacoustic (PA) imaging front-end, including the proposed LNA and a variable gain amplifier (VGA), was designed and fabricated in a 180 nm CMOS process. At 80 MHz, the front-end achieves an input-referred noise density of 1.36 nV/sqrt (Hz), an input return loss (S11) of better than −16 dB, a voltage gain of 37 dB, and a total harmonic distortion (THD) of −55 dBc while dissipating a power of 37 mW, leading to a noise efficiency factor (NEF) of 2.66.

P3Q-4 Nanocomposite Matching Layers for High Frequency Ultrasound Transducers

2006 ◽  
Author(s):  
K. K. Shung ◽  
J. M. Cannata ◽  
Q. F. Zhou ◽  
J. H. Cha ◽  
Y. Huang ◽  
...  
Keyword(s):  
High Frequency ◽  
Ultrasound Transducers ◽  
High Frequency Ultrasound ◽  
Frequency Ultrasound
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