Norimasa Nakashima

Development of a CUDA Implementation of the 3D FDTD Method

The use of general-purpose computing on a GPU is an effective way to accelerate the FDTD method. This paper introduces flexibility to the theoretically best available approach. It examines the performance on both Tesla- and Fermi-architecture GPUs, and identifies the best way to determine the GPU parameters for the proposed method.

Experimental Results on Energy Harvesting by Using AM Radio Broadcasting

Energy harvesting is the process of collecting small amounts of energies and converts them into electric power. Since power consumption of digital device has decreased, the energy harvesting is a good approach. The Fukuoka Institute of Technology is located near two AM radio broadcasting stations. Thus, a considerable electric power can be obtained by the electromagnetic waves radiated from these two stations. In this paper, we implement a rectifying antenna (rectenna) that coverts the electromagnetic waves into DC electric power. This rectenna is located at the place approximately 50 meters away from one of the AM radio broadcasting stations and provides a maximum power of 2.39 [mW]. Regarding this rectenna as a DC voltage source, the internal resistance and the electromotive force are 510 [kΩ] and 71.4 [V], respectively.

A prototype of rectenna with self-resonant antenna coil in AM radio frequencies

This paper focuses on the impedance characteristics of an antenna coil in the AM radio broadcast frequencies. Our experimentation reveals that a resonance occurs in a single antenna coil circuit in the above frequencies. The 8-turn antenna coil with 0.8 [m] diameter has the self-resonant frequency that is fairly agreement with a specific AM radio broadcast frequency. Using this phenomenon, namely, self-resonance, we make a prototype of rectenna for electromagnetic energy harvesting by using AM radio broadcast frequencies. This rectenna is located at the Fukuoka Institute of Technology which is 1347 [m] (about 5.6 wavelength) away from the specific AM radio broadcasting station. It provides the maximum power of 341 [μW]. Regarding this rectenna as the DC voltage source, the internal resistance and the electromotive force are 61.2 [kΩ] and 12.2 [V], respectively. A digital clock can operate by connecting to this rectenna.