Title: Analysis of Dual-electrode Piezoelectric Micromachined Ultrasonic Transducer
Speaker: Junxiang Cai
Time: 9:30-9:50, Sept. 3rd
Location: SIST3 301
Host: Tao Wu
Abstract:
We investigate the nonlinearity of Aluminum Nitride (AlN)-based dual-electrode Piezoelectric Micromachined Ultrasonic Transducer (PMUT). Various nonlinear vibration phenomena of PMUTs are observed when high AC voltage is applied to their inner and outer electrodes, respectively. The out-of-plane displacement driving capability and the impedance of inner and outer electrodes are compared. Utilizing nonlinear effects, we excited high-order mechanical harmonics with inner electrodes and obtained high-order electrical harmonics output at the outer electrodes. The designed PMUT boasts a resonant frequency of 177.9 kHz, where profound high-order harmonics can be vividly observed at the outer electrode. In contrast, at non-resonant frequencies like 250kHz, the emergence of high-order harmonic electrical signals is conspicuously absent. Additionally, the PMUT are more prone to exhibit nonlinear vibrations at resonance. These phenomena have the potential to be utilized in harmonic generation within acoustic-optical hybrid microsystems, sensing, and the radio frequency (RF) field.
Bio:
Junxiang Cai received the B.S. degree in physics from Shanghai Ocean University, Shanghai, China, in 2020, where he is currently pursuing the Ph.D. degree in electrical engineering. His research interests include the design and microfabrication techniques of piezoelectric microelectromechanical system (MEMS) resonators for RF and sensing applications.
Title: Characterization of AlN and AlScN thin films CPW Transmission on High-Resistive Substrates
Speaker: Kang Du
Time: 9:50-10:10, Sept. 3rd
Abstract:
AlN and AlScN are piezoelectric materials compatible with Cmos process, and achieving process interconnection on these two piezoelectric films is a reliable solution for integrating multiple functional devices in the future. However, there is limited research on transmission lines on Pizeo Si substrates. By designing coplanar waveguides, the linear energy transmission of coplanar waveguides on AlN and AlScN process platforms is compared. Analyze the factors affecting the performance of MPS-CPW. Evaluate the impact of interface parasitic conductivity effects that have existed in previous studies. Analyzed and explained the reasons for the performance differences between the two platforms. Further development can be made into a non-destructive method for testing the conductivity of contact interfaces between dissimilar materials.
Bio:
Kang Du received the B.S. degree in electronic science and technology from Huazhong University of Science and Technology, Wuhan, China, in 2020, where he is currently pursuing the master’s. degree in electronic science and technology . His research interests include the development of piezoelectric microelectromechanical systems (MEMS) and AlScN ferroelectric devices for radio frequency and sensing applications.
Title: Magnetic field control of lithium niobite thin film delay line
Speaker: Kang Du
Time: 10:10-10:30, Sept. 3rd
Abstract:
Benefiting from mature manufacturing processes and well-defined resonance frequencies, integrating magnetic materials into acoustic RF devices has opened up new avenues for controlling and enhancing the performance of acoustic devices. This study created a magnetically controllable Lamb wave delay line with a base frequency of 478 MHz, using a multiferroic heterostructure made of piezoelectric lithium niobate thin film and magnetic nickel thin film. We investigated the attenuation characteristics of the Lamb wave delay line corresponding to the horizontal shear mode at this operating frequency by varying the magnitude and direction of an applied magnetic field. The results showed that the attenuation of the delay line strongly depended on the magnitude and direction of the applied magnetic field, indicating a coupling between Lamb waves and ferromagnetic resonance.
Bio:
Mingye Du earned his B.S. degree in Measurement and Control Technology and Instrument from Zhengzhou University and joined ShanghaiTech University as a graduate student in 2021. He is currently pursuing Ph.D. degree in Electronics Science and Technology. His research interests include acoustic-magnetic coupling device, resonant infrared detector, acoustic delay line and Bio-MEMS.
Title: Wavelength-Scale Focusing Transducer Based on Suspended Aluminum Thin Film
Speaker: Jiawei Li
Time: 10:30-10:50, Sept. 3rd
Abstract:
Phononics is an emerging field that aims to control and manipulate the particles responsible for mechanical vibrations. Compared with electromagnetic waves, acoustic waves in solids have lower velocity and loss, enabling effective signal processing with smaller size. However, the current control level of phonon is far from their counterparts photons and electrons. The ability to focus and couple acoustic wave to wavelength-scale waveguide needs to be further explored. In this talk, a wavelength-scale focusing transducer based on suspended Aluminum nitride (AlN) piezoelectric thin film are designed, simulated and fabricated. The one port device was simulated and analyzed to verify the device focusing performance. Two-port acoustic delay line under different electrical configuration was simulated, fabricated and analyzed to evaluate the electro-acoustic transduction capability of the transducer. According to the simulation and measurenment results, the transducer is the potential component in phononic integrated circuit (PnIC).
Bio:
Jiawei Li earned his B.S. degree in electronic engineering from North China University of technology and joined ShanghaiTech University as a graduate student in 2021. He is currently pursuing Ph.D. degree in Electronics Science and Technology. His research interests include phononic integrated circuits and acoustic delay lines.
Title: Low Loss Acoustic Waveguide Based On 128° Y-cut Lithium Niobate
Speaker: Wenzhen Li
Time: 10:50-11:10, Sept. 3rd
Abstract:
Phononics is an emerging field that aims to control and manipulate the particles responsible for mechanical vibrations. Compared with electromagnetic waves, acoustic waves in solids have lower velocity and loss, enabling effective signal processing with smaller size. However, the current control level of phonon is far from their counterparts photons and electrons. The ability to focus and couple acoustic wave to wavelength-scale waveguide needs to be further explored. In this talk, a wavelength-scale focusing transducer based on suspended Aluminum nitride (AlN) piezoelectric thin film are designed, simulated and fabricated. The one port device was simulated and analyzed to verify the device focusing performance. Two-port acoustic delay line under different electrical configuration was simulated, fabricated and analyzed to evaluate the electro-acoustic transduction capability of the transducer. According to the simulation and measurenment results, the transducer is the potential component in phononic integrated circuit (PnIC).
Bio:
Jiawei Li earned his B.S. degree in electronic engineering from North China University of technology and joined ShanghaiTech University as a graduate student in 2021. He is currently pursuing Ph.D. degree in Electronics Science and Technology. His research interests include phononic integrated circuits and acoustic delay lines.
Speaker: Xuankai Xu
Time: 11:10-11:30, Sept. 3rd
Abstract:
Microwave acoustic devices offer significant advantages due to their small wavelengths, which are five orders of magnitude smaller than those of electromagnetic waves at the same frequency. This characteristic enables high-density integration and reduced crosstalk, facilitating efficient radio-frequency (RF) information processing within a compact footprint. The active control of on-chip acoustic waves has emerged as a critical area of interest, enabling the precise manipulation of RF information on a micro-scale. Thermo-acoustic (TA) phase modulators present an efficient method for controlling acoustic waves with minimal voltage requirements. Previous studies have primarily focused on surface acoustic wave (SAW) platforms, which face limitations such as restricted operating frequencies, high power consumption, and slow response times. In this talk, we introduce a thermo-acoustic phase modulator based on a Y36-cut lithium niobate (LN) thin-film platform. The proposed structure integrates a 450 MHz SH0 mode acoustic delay line (ADL) and an on-chip microheater for locally changing the temperature and thus controlling the phase of the ADL. Using this approach, we achieve a phase change of more than 281° at a heating power of 20 mW, and a modulation ability of 17°/mW in the linear modulation range, which is a 6.5 times improvement over previously reported bulk-LN platforms. Our thermo-acoustic modulators enable reconfigurable acoustic signal processing for next-generation wireless communication and microwave systems.
Bio:
Xuankai Xu received the B.S. degree in electrical engineering from Shenzhen University, Shenzhen, China, in 2021. He is currently pursuing a Master's degree in electrical engineering at ShanghaiTech University, Shanghai, China. His research interests focus on the design and development of piezoelectric RF MEMS, thermal MEMS, and multi-physics microsystems.
沪公网安备 31011502006855号
