|2F - Transverse Mode Analysis in SAW/BAW Devices
|Ken-ya Hashimoto, Chiba University, Japan
|Overview of topics covered
|Monday, October 22
|RF SAW/BAW devices are widely used in mobile communication systems. Although their technologies seems to be well developed, customers still need further enhancement of their performances.
Engineers believe lateral wave propagation is one of major sources of performance degradation in current RF SAW/BAW devices. It will cause unnecessary (spurious) resonances and/or energy leakage. Our goal is simple. It is to find a structure which can suppress spurious resonances without Q degradation for the main resonance. Recent Q enhancement in these devices makes this problem more difficult.
Combination of powerful computers and FEM tools allows us to analyze its behavior with acceptable accuracy. However, numerical analysis does not suggest how the optimal device structure should be designed and found.
This tutorial starts from physics and mathematical tretement of 2D wave propagation. Then wave propagation in waveguides and their operation principles and discussed in detail, and the discussion will be extended to wave excitation and scattering jn the structure. Influence of the Bragg reflection is also discussed. Next, the scalar potential theory is introduced as a powerful tool for the analysis, and not only propagation but also excitation of guided modes are discussed. Furthremore, the theory is extended to include coupling between two modes, and its impact is also detailed. Finally, various numerical techniques are introduced for the anlysis of the lateral mode behaviors and parameter extraction for the simulation model.
|Short CV of Instructor
| Ken-ya Hashimoto received his B.S. and M.S. degrees in electrical engineering in 1978 and 1980, respectively, from Chiba University, Chiba, Japan, and a Dr. Eng. degree in 1989 from Tokyo Institute of Technology, Tokyo, Japan. In 1980, he joined Chiba University as a research associate, and is now a professor of the University. He was a Visiting Professor of Helsinki University of Technology, Finland in 1998,. a Visiting Scientist of the Laboratoire de Physique et Metrologie des Oscillateurs, CNRS, France, in 1998-1999, a Visiting Professor of the Johannes Kepler University of Linz, Austria, in 1999 and 2001, a Visiting Scientist of the Institute of Acoustics, Chinese Academy of Science, Beijing, China in 2005-2006. a Visiting Professor of the University of Electronic Science and Technology of China, Chengdu, China, in 2009-2012, and now is a Guest Professor of Shangahi Jiatong University, Shanghai, China, from 2014.
In 2001, he served as a guest co-editor of the IEEETrans. on MTT Special Issue on Microwave Acoustic Wave Devices for Wireless Communications, and a publicity co-chair of the 2002 and 2015 IEEE International Ultrasonics Symposia. He was appointed to a member of the speaker’s bureau of the IEEE MTT-S. He also served as an International Distinguished Lecturer of the IEEE UFFC-S from 2005 to 2006, an ADCOM Member of the IEEE UFFC-S from 2007 to 2009 and from 2014 to 2016, a Distinguished Lecturer of IEEE ED-S from 2007 to 2009, and a general co-chair of the 2011 and 2018 IEEE International Ultrasonics Symposia. In 2015, he received the Ichimura Industrial Award from the New Technology Development Foundation for “Development of Optimal Substrate 42-LT for Radio Frequency Surface Acoustic Wave Devices”. In 2018, he received The Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology.
His current research interests include simulation and design of various high-performance surface and bulk acoustic wave devices, acoustic wave sensors and actuators, piezoelectric materials and RF circuit design.
Dr. Hashimoto is a Fellow of IEEE, and a Member of the Institute of Electronics, Information and Communication Engineers of Japan, the Institute of Electrical Engineers of Japan, and the Acoustical Society of Japan.