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Fiber optic birefringence enhanced accelerometer based on polarized modal interferometer
摘要： An inline fiber optic birefringence enhanced accelerometer (FOBEA) which applies one polarizer and a ten-meter high birefringence fiber wrapped on a transducer cylinder is proposed. Birefringence of polarized modes in panda polarization maintaining fiber (PMF) is enhanced by fiber coating and cylinders of different parameters. Accelerometers with copper cylinder (FOBEA-1) and polyurethane cylinder (FOBEA-2) are fabricated, the tested average sensitivities are 1.06rad/g (20-3800 Hz) and 16.97 rad/g (20-2000 Hz). The experimental results show the birefringence gain of FOBEA-1 is in good consistent with theoretical calculation of 1.07 and an additional birefringence gain of FOBEA-2 is 5.52 because the polyurethane cylinder works as fiber coating with the thickness of 1.21 mm. Temperature crosstalk is also investigated.
关键词： Polarized modal interferometer,Fiber optic accelerometer,Sensitivity,Transducer cylinder,Birefringence gain
更新于2025-11-28 14:23:57
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Effects of carbon nanotube thermal conductivity on optoacoustic transducer performance
摘要： CNT-PDMS composite is regarded as a promising candidate for optoacoustic transducer application. However, the relationship between the CNT thermal conductivity and optoacoustic transducer performance is still unde?ned. To explore this relationship, four types of CNTs with different diameters and lengths were employed to successfully fabricate four types of optoacoustic transducers. The thermal properties of CNTs were analyzed and discussed in this paper; the laser-generated ultrasound and optoacoustic conversion ef?ciency of the transducers were experimentally and theoretically investigated. Results of comparison revealed the CNT with a diameter and length of 8 nm and 10e30 mm, respectively, to have the highest thermal conductivity. With this type of CNT/PDMS composite, the optoacoustic conversion ef?ciency reached as high as 9.59 (cid:1) 10-3. Overall, the results demonstrate that higher CNT thermal conductivity corresponds to better optoacoustic transducer performance.
关键词： Laser-generated ultrasound,Thermal conductivity,Optoacoustic transducer,Optoacoustic conversion ef?ciency,CNT
更新于2025-09-23 15:23:52
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Surface Acoustic Wave Gyroscopic Effect in an Interdigital Transducer
摘要： The surface acoustic wave (SAW) gyroscopic effect in an interdigital transducer (IDT) deposited on a piezoelectric substrate is different from that in the piezoelectric substrate due to a reflection induced by IDT. In this work, an extended coupling-of-mode (COM) model including the gyroscopic effect and the reflection was developed to analyze the SAW gyroscopic effect. First, dispersion characteristics parameters of SAW were fitted according to the data derived using the finite element method (FEM). Then, variations of stop band edge frequency were calculated using the extended COM theory by integrating dispersion characteristics parameters into the COM model. We compared its results with those obtained via FEM analysis to confirm the proposed model's validity. We found that the variation in stop band edge frequency related to gyroscope effect reached the maximum value with a zero reflectivity value. For split IDT, the sensitivity of gyroscope effect is 0.036 Hz/rad/s with a lower than 1% normalized thickness. Conversely, the value of sensitivity was almost zero for bidirectional IDT and electrode width controlled single-phase unidirectional transducer (EWC/SPUDT).
关键词： interdigital transducer,surface acoustic wave,gyroscopic effect
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Auckland (2018.8.5-2018.8.8)] 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP) - Angle-Based Chipless RFID Tag and Its Application
摘要： This paper presents a novel angle-based chipless RFID tag with high capacity. It encodes the information with the angle between two arms of the X-shaped scatterer and is identified through the orthogonal polarization. The advantage of this type of tag is that every unit can encode multi-bit information. Also, for different codes of one unit, the proposed tag occupies the same spectrum. This is helpful to improve the spectrum efficiency. Based on this, the tag is used to design the resistance transducer.
关键词： transducer,orthogonal polarization,Chipless RFID,space angle
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - High Voltage Excitation and Nonlinear Transmission of a 16 MHz AlN-Based Piezoelectric Micro-Machined Ultrasonic Transducer
摘要： This paper reports the performance of a 25 μm AlGaN-based micro-piezoelectric transducer (MPT) under high voltage excitation and determination. The proposed MPT array consists of 23×28 elements fabricated on a silicon-on-insulator (SOI) substrate with 1 μm AlGaN thin film on 24 μm silicon membrane. With all the array elements electrically connected together, the electric impedance of the MPT was 11.5–7.22 kΩ at 24.7 MHz resonance frequency in air and 3.21–7.24 kΩ at 22.8 MHz when the device was water charged. The laser Doppler vibrometer (LDV) measurements showed that the transmission efficiency and the bandwidth for free vibration were 1.6 nm/V and 1.0%, respectively. The resonance modes were specifically associated with the material parameters and the initial state of the device. Moreover, nonlinear behavior was observed when increasing the input mean power exceeded 24 mW. This strategy is potentially applied to CMOS-compatible high-resolution ultrasound imaging.
关键词： AlGaN,CMOS-compatible,Ultrasound,High voltage,Micro-piezoelectric transducer
更新于2025-09-23 15:22:29
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Defects and Improvements of Pockels Transducer Voltage Segmentation
摘要： The sensing range and sensitivity of optical voltage transducer are badly limited by the inherent half-wave voltage of the electro-optic crystals and a nonlinear polarization demodulation based on Malus’ law. A multi-segmented structure can meet the requirement of the half-wave voltage but is only suitable for 500 kV and above voltage levels with incident wavelength of 632.8 nm, but it is not suitable for all voltage levels if the incident wavelength is greater than 1330 nm. By the way in the multi-segmented structure its optical path and devices are deviated easily by vibrations and thermal expansion and contraction. In this paper, the multi-segmented structure is improved to be suitable for various high-voltage levels with the wavelength of 632.8 nm or greater, and moreover, a new approach is presented to use MgTiO3 ceramics to enwrap around BGO (Bi4Ge3O12) crystal to reduce the integral voltage errors from 0.260% to 0.012%.
关键词： high voltage measurement,Optical voltage transducer,multi-segmented structure,integral voltage error
更新于2025-09-23 15:22:29
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Eco-friendly highly sensitive transducers based on a new KNN-NTK-FM lead-free piezoelectric ceramic for high-frequency biomedical ultrasonic imaging applications
摘要： High-frequency ultrasonic imaging with improved spatial resolution has gained increasing attention in the field of biomedical imaging. Sensitivity of transducers plays a pivotal role in determining ultrasonic image quality. Conventional ultrasonic transducers are mostly made from lead-based piezoelectric materials that may be harmful to the human body and the environment. In this study, a new (K,Na)NbO3-KTiNbO5-BaZrO3-Fe2O3-MgO (KNN-NTK-FM) lead-free piezoelectric ceramic was utilized in developing eco-friendly transducers for high-frequency biomedical ultrasonic imaging applications. A needle transducer with a small active aperture size of 0.45 × 0.55 mm2 was designed and evaluated. The transducer exhibits great performance with a high center frequency (52.6 MHz), a good electromechanical coupling (keff ~ 0.45), a large bandwidth (64.4% at -6 dB), and a very low two-way insertion loss (10.1 dB). Such high sensitivity is superior to those transducers based on other lead-free piezoelectric materials and can even be comparable to the lead-based ones. Imaging performance of the KNN-NTK-FM needle transducer was analyzed by imaging a wire phantom and an agar tissue-mimicking phantom. Imaging capabilities of the transducer were further demonstrated by ex vivo imaging studies on a porcine eyeball and a rabbit aorta. The results suggest that the KNN-NTK-FM piezoceramic has many attractive properties over other lead-free piezoelectric materials in developing eco-friendly highly sensitive transducers for high-frequency biomedical ultrasonic imaging applications.
关键词： lead-free piezoelectric ceramic,Biomedical ultrasonic imaging,high-frequency ultrasonic transducer,eco-friendly
更新于2025-09-23 15:21:21
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[IEEE 2019 Joint Conference of the IEEE International Frequency Control Symposium anEuropean Frequency and Time Forum (EFTF/IFC) - Orlando, FL, USA (2019.4.14-2019.4.18)] 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC) - Support Transducer Enabled Single Resonator Channel Select Filter
摘要： In this work, we report a piezoelectric channel select filter design using a single resonator which utilizes Thin Piezo on Substrate (TPoS) transducer uniquely positioned so as to drive the central bulk Single Crystal Silicon (SCS) into resonance. Here, the support transducers operate in a combined length extension and an in-plane shear mode. A short connector between transducers and central SCS is used to create a frequency split to realize the filter. The device is fabricated using MEMSCAP Inc. AlN-on-silicon platform. A differential drive and single port sense method was employed to realize the narrow bandwidth (NBW) filter with a reduced feedthrough level. As a result, we demonstrate a 20.62 MHz TPoS MEMS filter with an extremely flat passband and a tiny bandwidth of 18 kHz (0.087% BW), a 4dB Insertion Loss with a 39dB Stop Band Rejection and less than 0.1dB passband ripple.
关键词： Channel select filter,differential,piezoelectric,narrow bandwidth,TPoS,support transducer
更新于2025-09-23 15:21:01
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Optimizing the light delivery of linear-array-based photoacoustic systems by double acoustic reflectors
摘要： Although linear transducer arrays have been intensely used in photoacoustic imaging, their geometrical shape constrains light illumination. Today, most linear array based photoacoustic systems utilize side-illumination geometry, which consists of two line fiber bundles attached to the side of the probe. The angled light illumination increases the light travel distance in deep tissue, consequently limiting the imaging depth. This issue was partially addressed by adding a right angle prism in front of the transducer. While this design makes the light illumination and acoustic detection co-axial, the transducer and the fiber bundles are orthogonal to each other, making the system inconvenient for handheld use. To overcome this limitation, here we propose a double-reflector design, in which the second reflector redirects the acoustic signals by another 90°, so that the transducer and the fiber bundle are now parallel to each other. In this design, both the transducer and fiber bundle output are fitted into a compact housing for convenient handheld imaging. To evaluate the efficiency of our design, we performed various phantom and human in vivo experiments. Our results demonstrate that the double-reflector design indeed provides deeper imaging depth and it also allows for easy imaging of objects with uneven surfaces.
关键词： handheld imaging,photoacoustic imaging,co-axial illumination,double-reflector design,linear transducer arrays
更新于2025-09-23 15:21:01
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CaBi <sub/>4</sub> Ti <sub/>4</sub> O <sub/>15</sub> -based lead-free sol–gel composites for high-temperature application
摘要： CaBi4Ti4O15 (CBiT)-based lead-free sol–gel composites were developed for high-temperature ultrasonic transducer application. In this study, two types of lead-free sol–gel solution, Ba0.7Sr0.3TiO3 (BST) and Bi4Ti3O12 (BiT), were used for consistency to fabricate >50-μm-thick CBiT/BST and CBiT/BiT ?lms on 3-mm-thick titanium substrates by a sol–gel spray technique. BST and BiT were chosen because of their high dielectric constant and high Curie temperature, respectively, in addition to their being lead-free materials. A thermal cycle test was carried out between RT and 600 °C, and clear multiple echoes were con?rmed during three thermal cycles for both materials. In addition, the sensitivity of CBiT/BiT was higher than that of CBiT/BST although a higher poling temperature is required for CBiT/BiT. Therefore, an ultrasonic transducer potential for high-temperature application was successfully demonstrated. ? 2018 The Japan Society of Applied Physics
关键词： ultrasonic transducer,high-temperature,sol–gel composites,lead-free,CaBi4Ti4O15
更新于2025-09-23 15:21:01