Ken Ya Hashimoto   Xinyi Li   Jingfu Bao   Luyan Qiu   Tatsuya Omori   
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 67(7) 1479-1484 2020年7月
This article describes derivation of an equivalent circuit for nonlinear responses in film bulk acoustic resonators from the first-order perturbation analysis using the piezoelectric constitutive equations with the h-form. For simplicity, electrod...
Xinyi Li   Jingfu Bao   Yulin Huang   Benfeng Zhang   Tatsuya Omori   Ken Ya Hashimoto   
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 66(12) 1920-1926 2019年12月
This article describes the application of the hierarchical cascading technique (HCT) to the 3-D finite-element method (FEM) analysis of transverse-mode behaviors in surface acoustic-wave (SAW) devices. Mirror cascading is proposed as a speed-up te...
Naoto Matsuoka   Tatsuya Omori   Ken Ya Hashimoto   
IEEE International Ultrasonics Symposium, IUS 2019-October 1231-1234 2019年10月
This paper describes a suppression technique for the lowest-order plate mode in wafer bonded surface acoustic wave (SAW) devices using LiTaO3 (LT) thin plate. When LT plate thickness is close to the SAW wavelength, say micron order, the lowest-ord...
Akihiro Iyama   Xinyi Li   Jingfu Bao   Naoto Matsuoka   Tatsuya Omori   Ken Ya Hashimoto   
IEEE International Ultrasonics Symposium, IUS 2019-October 1235-1238 2019年10月
This paper describes 3D FEM simulation of scattering at a border between IDT and reflector in SAW resonators using hierarchical cascading technique and general purpose graphic processing unit. SH-type SAW on the 42°YX-LiTaO3 substrate is chosen. I...
Ken Ya Hashimoto   Xinyi Li   Jingfu Bao   Luyan Qiu   Tatuya Omori   
IEEE International Ultrasonics Symposium, IUS 2019-October 173-176 2019年10月
This paper describes derivation of an equivalent circuit for nonlinear responses in film bulk acoustic resonators from the first-order perturbation analysis using the piezoelectric constitutive equations with the h-form. For simplicity, electrodes...
Fumiaki Ukaji   Chang Jun Ahn   Tatsuya Omori   Ken Ya Hashimoto   
Proceedings of the IEEE International Conference on Industrial Technology 2016-May 860-865 2016年5月
Multi-user multi-input multi-output (MU-MIMO) can achieve more transmission speed and multi-user diversity. Furthermore, since frequency symbol spreading (FSS) can mitigate the effect of frequency selective fading, it is useful for improving the B...
Masaya Okamura   Chang Jun Ahn   Tatsuya Omori   Ken Ya Hashimoto   
2015 International Symposium on Intelligent Signal Processing and Communication Systems, ISPACS 2015 532-536 2016年3月
Massive MIMO has been recognized as promising ways to provide high speed data transmission. However, since the number of pilot symbol is proportionally depending on the number of transmit antenna, the total transmission rate of massive MIMO would ...
Kotaro Abe   Chang Jun Ahn   Tatsuya Omori   Ken Ya Hashimoto   
2015 International Symposium on Intelligent Signal Processing and Communication Systems, ISPACS 2015 417-421 2016年3月
Recently, visible light communication(VLC) is widely researched due to the spreading of LED usage. It satisfies demands of ubiquity and high speed communication. However, it is impossible to transmit the phase information and frequency information...