Frequency selective EMI shield for “quiet hospital wards”

• Main Author: Tan, Alex Boon Siu.
• Other Authors: See Kye Yak
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Control and instrumentation::Medical electronics
• Online Access: http://hdl.handle.net/10356/45851
• Institution: Nanyang Technological University

As more medical electronics are being employed in hospitals, these wards would require visitors to switch off their mobile phones so as to prevent mobile phones from causing erroneous readings or stoppage of life sustaining medical equipment. Therefore, it is becoming critical to ensure electromagnetic interference (EMI) on such medical devices be minimized. This project proposes the combination of theory and design of frequency selective surfaces (FSS) with EMI shielding to selectively reject strong electromagnetic (EM) waves in the GSM and Wi-Fi band. The approach to this problem requires an understanding of electromagnetic shielding, FSS and the use of 3D EM simulation. Hence after designing a band stop EMI shield with advanced full wave modeling, a planar screen will be fabricated to validate actual performance with simulation results. An EMI shield with multi-band stop performance is designed and successfully implemented. The EMI shield is a flexible, light weight and printed on a transparent material fabricated using screen printing technique. The FSS shield‟s application and effectiveness is demonstrated in a shielding room and another using a small enclosure. The shielding effectiveness (SE) is measured using a dual horn antenna approach in a shielded enclosure. The objective to attenuate undesired frequencies bands using passive shielding techniques were achieved (at least 10dB).