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Recent advances in thin-film transfer and ferroelectric poling have enabled the realization of multilayer piezoelectric films with spatially dependent polarization. Consequently, while conventional piezoelectric acoustic design leverages single orientations, researchers have recently begun exploring periodically poled piezoelectric films (P3Fs) to enhance performance. These platforms open the […]

This work demonstrates novel high-overtone bulk acoustic resonators (HBARs) with only top electrodes using an epitaxial ε-Ga2O3 piezoelectric film grown on conductive 4H-SiC substrates. The device exhibits a broad frequency response spanning 1–8 GHz, with a free spectral range (FSR) of 18.6 MHz between adjacent modes. Key performance metrics include an f⋅Q product exceeding $1.2\times […]

Dynamic strain and temperature are critical physical quantities to be monitored in industrial environments to assure safe operational conditions and to diagnose for required maintenance. Dynamic strain and temperature feedback signals are particularly important for equipment and structural health monitoring (SHM) applications in aerospace, automotive, power generation, and advanced manufacturing. […]

Ultrasound (US) is a promising modality for wirelessly powering implantable devices, requiring encapsulated receivers to ensure long-term stability. Traditional hermetic packaging often limits acoustic transmission, making polymer-based encapsulation a more suitable alternative. This study investigates how implant-grade polymers, thermoplastic polyurethane (TPU), parylene-C, and medical-grade […]

Ultrasonic attenuation can be used to characterize tissue properties of the human breast. Both quantitative ultrasound (QUS) and ultrasound tomography (USCT) can provide attenuation estimation. However, limitations have been identified for both approaches. In QUS, the generation of attenuation maps involves separating the whole image into different data blocks. The optimal size of the data block […]

Advances in 4-D ultrasound imaging open new perspectives in biomedical research by reducing the long-standing challenge of operator dependency. Extensive research efforts are focused on developing next generation of 2-D transducer arrays for 4-D imaging. Here, we present a compact 2-D array design based on hexagonal-shaped transducer elements. We demonstrate that 2-D hexagonal arrays provide an […]

The acoustic angiography leverages the superharmonic response of microbubbles against linear tissue to generate 3-D maps of microvasculature. This contrast-enhanced ultrasound imaging approach uses dual-frequency (DF) transducers that transmit at frequencies less than 5 MHz and receive at frequencies three times or greater than the fundamental frequency to selectively detect microbubble signals. […]

The power Doppler (PD) ultrasound imaging provides high-quality, noninvasive visualization of blood flow and has the potential to be used for circulation screening. However, its application in human arterial imaging remains challenging due to the presence of complex hyperechoic moving structures (HMSs). In this study, we propose an adaptive singular value decomposition (SVD) filtering strategy […]

3-D ultrasound localization microscopy (ULM) enables comprehensive mapping of microvascular networks by providing micrometer-scale spatial resolution while avoiding projection errors inherent to 2-D ULM imaging. Current 3-D ULM techniques are based on linear pulse sequences combined with spatiotemporal filtering to distinguish microbubble flow from tissue signals. However, singular-value […]