Congratulations to Fen Xia on her successful PhD dissertation defense

Fig. 1: Congratulations to Fen Xia on her successful PhD dissertation defense, and thanks for Chair Professor Mohamad Sawan on her supervision of this thesis project！

On June 12, a School of Engineering dissertation defense was held in room E5-244, Westlake University. Fen Xia, a PhD candidate of CenBRAIN Neurotech Center of Excellence, successfully defended her doctoral dissertation having the title "Research on Wireless Neurostimulator-on-Chip with Minimal Invasiveness for Apnea Management".

Professor Shurong Dong from Zhejiang University was invited to be the chair of the defense committee, Professor William Shieh from Westlake University, Professor Qingxin Chu and Professor Chunxu Mao from South China University of Technology, Professor Xiaoguang Liu from Southern University of Technology were the members of the defense committee. Dr. Guoguang Rong, Research Full Professor in Westlake University, was the secretary of this evaluation committee. Several CenBRAIN Neurotech Center of Excellence members attended this defense.

Ph.D Graduate

“I express my sincere gratitude to my supervisor, Professor Mohamad Sawan, for affording me the opportunity to pursue my Ph.D. studies under his esteemed guidance. Throughout my academic journey, his exceptional tolerance, constant patience, and consistent direction have been invaluable assets. Designing the proposed system on chip has presented me with numerous challenges, often leaving me feeling frustrated. However, Professor Sawan was always readily available to address my queries regarding simulations or experimental testing with immediate and thoughtful explanations. His relentless pursuit of perfection has continuously motivated me to fearlessly pursue excellence in my own work. ”

Dr. Fen Xia’s research interests include the design of wireless power transfer system and implantable medical device, the synthesis and design of microwave passive components, microwave analog signal processing, non-invasive brain imaging based on microwave technique, integrated circuits, and FDTD techniques. During her PhD study at CenBRAIN Neurotech, she has published five papers as first author, four patents are pending. Besides, Dr. Fen received several honorary titles, such as Zhejing University Outstanding PhD Student, Outstanding PhD Leader, Arts and Sports Award and then she will graduate the PhD degree from Zhejiang University with outstanding mention.

Ph.D Thesis Abstract

Obstructive sleep apnea (OSA), a common sleep disorder, affects approximately one billion people worldwide. Treatment with hypoglossal nerve stimulators has successfully restored health in up to 76% of patients. Traditional hypoglossal nerve stimulators consist of stimulating wires placed around the hypoglossal nerve, a stimulating generator positioned below the left clavicle, and a respiratory sensor installed parallel to the rib in the fourth intercostal space. Notably, the battery and respiratory sensor in the implanted device occupy significant space, increasing trauma for patients.

To address the excessive invasiveness of traditional hypoglossal nerve stimulators, Fen Xia's Ph.D. dissertation designed and implemented a novel, smaller hypoglossal nerve stimulator based on wireless power transfer technology and external respiratory detection. The system's external parts use electrocardiography and OSA monitors to analyze abnormal breathing patterns and transmit power and stimulation signals to the internal device. Energy and data transfer between the external and internal devices are achieved through a pair of coils. Additionally, the paper proposes a coil design procedure aimed at achieving optimal transmission efficiency under predetermined load resistance.