We explore a phononic crystal Luneburg lens through design, fabrication, and analysis for omnidirectional elastic wave focusing enhanced energy harvesting both numerically experimentally. The proposed is formed using hexagonal unit cells with blind holes of different diameters, which are determined according to the refractive index distribution obtained by finite-element simulations lowest asymmetric mode Lamb band structure. Wave performed under plane excitation from line source, observed...

Intravascular ultrasound (IVUS) and intracardiac echography (ICE) catheters with real-time volumetric imaging capability can provide unique benefits to many interventional procedures used in the diagnosis treatment of coronary structural heart diseases. Integration capacitive micromachined ultrasonic transducer (CMUT) arrays front-end electronics single-chip configuration allows for implementation such catheter probes reduced interconnect complexity, miniaturization, high mechanical...

We explore the enhancement of structure-borne elastic wave energy harvesting, both numerically and experimentally, by exploiting a Gradient-Index Phononic Crystal Lens (GRIN-PCL) structure. The proposed GRIN-PCL is formed an array blind holes with different diameters on aluminum plate, where hole distribution tailored to obtain hyperbolic secant gradient profile refractive index guided finite-element simulations lowest asymmetric mode Lamb band diagrams. Under plane excitation from line...

This paper describes the design of CMOS receiver electronics for monolithic integration with capacitive micromachined ultrasonic transducer (CMUT) arrays high-frequency intravascular ultrasound imaging. A custom 8-inch (20-cm) wafer is fabricated in a 0.35-μm two-poly, four-metal process and then CMUT are built on top application specific integrated circuits (ASICs) wafer. We discuss advantages single-chip CMUT-on-CMOS approach terms receive sensitivity SNR. Low-noise high-gain...

In this paper, several innovative steps used in fabricating surface micromachined capacitive ultrasonic immersion transducers are reported. The investigation is focused on major the device fabrication processes necessary to optimize transducer performance. Such include membrane formation, vacuum sealing, and electrode metallization. Three structures evaluated: a nitride with an oxide sacrificial layer; polysilicon layer. sealing mechanisms compared, each of which requires different degree...

In this paper, we report on the characterization of 1-D arrays capacitive micromachined ultrasonic transducers (cMUT). A 275- x 5600-micron CMUT array element is experimentally characterized, and results are found to be in agreement with theoretical predictions. As a receiver, transducer has 0.28-fm/square root Hz displacement sensitivity, and, as transmitter, it produces 5 kPa/V output pressure at surface 3 MHz DC bias 35 V. The more than 100% fractional bandwidth around MHz, which makes...

In this study, a 64-element, 1.15-mm diameter annular-ring capacitive micromachined ultrasonic transducer (CMUT) array was characterized and used for forward-looking intravascular ultrasound (IVUS) imaging tests. The manufactured using low-temperature processes suitable CMOS electronics integration on single chip. measured radiation pattern of 43 /spl times/ 140-/spl mu/m element depicts 40/spl deg/ view angle around 15-MHz center frequency in agreement with theoretical models. Pulse-echo...

In this paper, a bulk acoustic resonator based on ZnO belts is demonstrated. This device shows great deal of promise in applications as an electronic filter and mass sensor. The fabricated was characterized using vector network analysis, both the first third harmonics resonance were observed at approximately 247 754 MHz, respectively. A one-dimensional Krimholt−Leedom−Matthaei model utilized to predict resonant frequency confirm behavior.

A miniature differential microphone is described having a low-noise floor. The sensitivity of suffers as the distance between two pressure sensing locations decreases, resulting in an increase input sound pressure-referred noise In here, both diaphragm thermal and electronic are minimized by combination novel design use optical that has been integrated into package. measures 1×2mm2 fabricated out polycrystalline silicon. based on coupled directionally sensitive ears fly Ormia ochracea....

One of the most important promises capacitive micromachined ultrasonic transducer (CMUT) technology is integration with electronics. This approach required to minimize parasitic capacitances in receive mode, especially catheter-based volumetric imaging arrays, for which elements must be small. Furthermore, optimization available silicon area and minimized number connections occurs when CMUTs are fabricated directly above associated Here, we describe successful fabrication performance...

Despite the challenges in treating glioblastomas (GBMs) with immune adjuvants, increasing evidence suggests that targeting cells within tumor microenvironment (TME) can lead to improved responses. Here, we present a closed-loop controlled, microbubble-enhanced focused ultrasound (MB-FUS) system and test its abilities safely effectively treat GBMs using checkpoint blockade. The proposed fine-tune exposure settings promote MB acoustic emission-dependent expression of proinflammatory marker...

A maximum processing temperature of 250/spl deg/C is used to fabricate capacitive micromachined ultrasonic transducers (CMUTs) on silicon and quartz substrates for immersion applications. Fabrication provides a means electronics integration via post-complementary metal oxide semiconductor (CMOS) without sacrificing device performance. reduces parasitic capacitance allows the use optical displacement detection methods CMUTs. The simple, low-temperature process uses metals both as sacrificial...

Visualization and scaling of drop-on-demand continuous-jet fluid atomization water are presented to elucidate the physics ejection process characterize modes operation a novel micromachined ultrasonic droplet generator. The device comprises reservoir that is formed between bulk ceramic piezoelectric transducer an array liquid horn structures wet etched into (100) silicon. At resonance, generates standing pressure wave within cavity focused at tip nozzle by structure. Device has been...

We introduce a novel probe structure for the atomic force microscope. The has sharp tip placed on micromachined membrane with an integrated displacement sensor, diffraction-based optical interferometer. use this in microscope to directly measure transient interaction forces between and sample when operating dynamic mode. form images related viscoelasticity adhesion of samples by recording salient features individual tap signals. also produce tapping mode topography order magnitude faster...

A micromachined accelerometer device structure with diffraction-based optical detection and integrated electrostatic actuation is introduced. The sensor consists of a bulk silicon proof mass electrode that moves vertically respect to rigid diffraction grating backplate provide interferometric resolution the proof-mass displacement when illuminated coherent light. architecture includes monolithically port enables application precisely controlled broadband forces while simultaneously...

This paper describes a low-power approach to capacitive sensing that achieves high signal-to-noise ratio (SNR). The circuit is composed of feedback charge amplifier and adaptation circuit. Without the circuit, only consumes 1 muW achieve audio band SNR 69.34 dB. An scheme using Fowler-Nordheim tunneling channel hot-electron injection mechanisms stabilize dc output voltage demonstrated. provides very low frequency pole at 0.2 Hz. measured noise spectrums show this slow-time scale does not...

We describe a three-dimensional (3D) finite element analysis model of the contact between an atomic force microscopy (AFM) tip and substrate with size subsurface structures. The can simulate stiffness measured by scanning AFM on surface sample buried nanoscale In addition to analytical verification convergence analysis, we present results experimental study. For this purpose, use acoustic setup special silicon samples well defined cavities fabricated focused ion beam techniques. 3D is also...

Having intravascular ultrasound (IVUS) imaging capability on guide wires used in cardiovascular interventions may eliminate the need for separate IVUS catheters and expand use of a larger portion vasculature. High frequency capacitive micro machined ultrasonic transducer (CMUT) arrays should be integrated with interface electronics placed wire this purpose. Besides small size, system-on-a-chip (SoC) front-end connect to back-end system minimum number preserve critical mechanical properties...

This letter presents micromachined two-dimensional array flextensional transducers that can be used to generate sound in air or water. Individual elements consist of a thin piezoelectric ring and thin, fully supported, circular membrane. We report on an optimum design for individual element based finite modeling. manufacture the transducer arrays using planar silicon micromachining demonstrate ultrasound transmission at 2.85 MHz. Such could combined with on-board driving addressing circuitry...

An integrated optical interferometric detection method for micromachined capacitive acoustic transducers is reported. The back electrode of the transducer on a transparent substrate shaped as an diffraction grating and displacement membrane determined with resolution by measuring intensity reflected orders. By applying voltage to deflect electrostatically, sensitivity kept at optimum level transmission signals are generated. Initial experiments devices microfabricated quartz substrates show...