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It is critical to use a proper spatial sampling, otherwise images suffer from grating lobes. However, the cost of a medical ultrasound scanner is strongly related to the channel count of the receive electronics. This has led to channel reduction using multiplexing or in-probe pre-beamforming methods at the cost of image quality or frame rate. An alternative is to reduce the receive channel count and...
The constantly rising demand for higher data rates is addressed by advanced communication standards like carrier aggregation (CA) in combination with LTE. The increased complexity of the RF frontend has put tremendous pressure on improving linear performance of BAW filters over the last years. On top of that a large number of intermodulation (IMD) specification have been added to safeguard all CA...
Performance of AlN-based electroacoustic devices directly tie with piezoelectric and metal electrode film quality. In this paper, sputter techniques for the reactive sputtering of AlN and ScAlN thin films, for the deposition of highly textured metal electrodes, and for the deposition of multilayer Bragg acoustic reflectors for SMR devices using dual-target S-gun magnetrons are described and some film...
Fast acquisition sequences enable >200Hz 2D cardiac B-mode imaging with little compromise in image quality. Fast imaging minimizes frame to frame decorrelation, enabling RF-based tracking for enhanced signal-to-noise ratio (SNR) in motion and deformation imaging. Our objective was to evaluate the performance and hypothesize on the clinical usefulness of Fast RF-based Tracking (FRFT) in comparison...
Partial substitution of Al by Sc in AlN wurtzite films leads to a strong enhancement of the piezoelectric properties as long as the wurtzite phase is maintained. This is very promising for improving piezoelectric MEMS devices and enlarging their application range. Nucleation of (0001)-AlScN works particularly well on Pt (111) thin films. However, in some applications, the growth on insulating substrates...
Energy harvesting from surrounding electromagnetic wave can satisfy the increasing demand of trillions of wireless sensors for IoT. RF energy harvesting is generally achieved by RF-DC conversion using a rectifying antenna (called rectenna). For weak RF signal, however, RF-DC conversion efficiency significantly decreases because weak RF signal cannot activate the diode in the rectenna. Therefore, in...
Fast acquisition sequences enable >200Hz 2D cardiac B-mode imaging with little compromise in image quality. Fast imaging minimizes frame to frame decorrelation, enabling radiofrequency (RF)-based tracking for enhanced signal-to-noise ratio (SNR) in motion and deformation imaging. Our objective was to compare the performance and clinical usefulness of Fast RF-based Tracking (FRFT) to the established...
Bulk thermal ablation, including radiofrequency ablation (RFA) as well as microwave and ultrasound (US) ablation, is an important approach to tumor treatment. To avoid incomplete treatments and cancer recurrence while reducing morbidity, a real-time monitoring and control approach, capable of providing consistent thermal ablation in minimum time, is needed. Echo decorrelation imaging has been successfully...
Design of side edges is one of the most important tasks for realization of high performance RF SAW/BAW devices. For the purpose, the authors proposed an FEM based technique where the specified mode is injected to the border under concern through a damping mechanism, and scattering coefficients are estimated from calculated BAW field [1]. Even though this technique is effective, its setup is too complicated...
Enegy harvesting from surrounding electromagnetic wave have attracted much attention in recent years. Low RF-DC conversion efficiency in the rectenna due to a weak power of electromagnetic wave is a problem. We here report the new type of polarization inverted FBAR transformer for RF amplification in the rectenna. c-Axis zig-zag polarization inverted 12 layer ScAlN was fabricated by glancing sputtering...
The authors developed phase-sensitive and fast mechanical scanning laser probe system as a diagnosis tool for RF SAW/BAW devices[1]. Captured 2D image of wave field brings valuable information such as energy leakage and standing wave pattern with a help of a wavenumber domain analysis[2] for a specified driving frequency. Although the system is frequently used by external researchers and engineers...
It is more difficult to nucleate AlN-ScN alloy thin films (AlScN) in pure (0001)-texture than it is with pure AlN thin films. AlN thus can serve as seed layer for AlScN. Equipment limitations may lead to the problem of a vacuum break between AlN and AlScN deposition, as it leads to oxidation of the AlN surface. This issue was studied with high resolution TEM and electron diffraction. The formed oxide...
An effective imaging modality to delineate the ablated region after microwave ablation (MWA) therapy is crucial to yield promising treatment outcomes. Ultrasound B mode imaging is widely used to guide the ablation needle. However, the image quality suffers from relatively low imaging contrast due to the similar echogenicity between the ablated and surrounding liver tissue. In this study, we applied...
We have designed and implemented an ultrasonic imaging research platform that performs all signal processing, including beamforming and image processing, using software on a GPU. An operating software is developed on a PC that can control RF data acquisition hardware to accommodate ultrasound images of various formats. Beamforming methods that include conventional scan line based imaging, scan line-based...
RF filtering technologies based on piezoelectric MEMS resonators have been successfully developed and commercialized in the past decade thanks to their size and outstanding performance. The challenge to enhance filter's performance in terms of lower insertion losses and wider bandwidth still makes for an active research topic, especially spurring the interest for new classes of materials such as doped-AlN...
In this paper we propose a computer-aided diagnosis system for the breast lesion classification. Our approach is based on quantitative ultrasound and deep learning. We used the Nakagami imaging to create parametric maps of breast lesions that illustrate tissue scattering properties. For this task the sliding window technique was applied. The Nakagami parameter was calculated using the maximum likelihood...
Cervical spine pathoanatomy is typically evaluated by static radiographs, CT or MRI; however, these modalities are unable to directly measure the dynamic performance of the spine that account for its functionality. We have developed an ultrasound based technique that provides a non-invasive, realtime, quantitative, textitin-vivo image of the C-spine that allows for assessment of the dynamic motion...
Previous work has shown that the degree of anisotropy in tissue can be assessed using Acoustic Radiation Force Impulse (ARFI) imaging performed with a geometrically asymmetric excitation. In this work, we investigate the clinical relevance of mechanical anisotropy in Duchenne muscular dystrophy (DMD). Anisotropy assessment was performed using relative elasticity (RE) and relative viscosity (RV) parameters...
Ultrafast imaging based on plane wave (PW) / diverging wave (DW) is an active area of research in ultrasound acquisitions because of its capacity of reaching high frame rate. Beamforming of received echoes in Fourier domain provides comparable image quality but lower computational complexity with respect to the conventional DAS approach [Zhang et al., UFFC, 2016]. However, the current state-of-the-art...
The Reference Phantom Method can be used to quantify acoustic properties of tissue by compensating for system effects using the average power spectrum from a well-characterized homogeneous medium. Widespread clinical application of the Reference Phantom Method is hindered by the need to scan the reference phantom using the same transducer, system, and system settings as used for scanning the tissue...
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