Near-field magnetic induction (NFMI) is a short range wireless technology that uses loop antennas coupled by a magnetic field. NFMI antennas are electrically small and thus extremely inefficient and narrow band, making system design for multi-user and high-bitrate applications challenging. The goals of this thesis are to develop a test platform suitable for NFMI antenna testing, to model, design and test NFMI antennas that have high bandwidth-efficiency, and to explore the possibility of using MIMO (multiple-input multiple-output) to increase the capacity of the NFMI channel. This thesis provides system implementations, test results, and channel modeling to aid in the design of future NFMI systems. Implementation of a multi-channel discrete-time wireless system are provided for PC-based software and FPGA-based firmware as a platform for antenna testing. Optimized antenna designs in terms of efficiency and bandwidth are presented, achieving the theoretical bandwidth-efficiency bound for small antennas. Preliminary modeling and simulation results for the NFMI-MIMO channel are included, which show that the information-theoretic capacity of the NFMI-MIMO channel is approximately double the standard single-antenna NFMI capacity at 10 bits/s/Hz.
College and Department
Ira A. Fulton College of Engineering and Technology; Electrical and Computer Engineering
BYU ScholarsArchive Citation
Gottula, Ronald Brett, "Discrete-Time Implementation, Antenna Design, and MIMO for Near-Field Magnetic Induction Communications" (2012). All Theses and Dissertations. 3324.
near field magnetic induction, wireless communications, MIMO