2021 年 25 巻 3 号 p. 93-101
In this paper, we evaluate the system of wireless distributed computing (WDC) including a 1×2 array Yagi-antenna de-signed for the system. This antenna is developed on a glass-epoxy printed circuit board and its geometry is as compact as 1.6×150×200 mm3. The double rat-race balun, which also works as a power divider of the array, greatly reduces insertion losses from the RF port to driver elements of the antenna and greatly increases the operational bandwidth. As a result, the insertion loss is about 2 dB and the antenna operates from 2.1 to 2.5 GHz. Since the double rat-race balun also has good isolation between the ports of the arrayed driver elements, this array antenna seems to be driven with independent RF signals and achieves the high gain of 13.0 dBi. The radiation pattern of this antenna is suitable for WDC. Since the half-power beamwidth of the azimuth angle is wider than that of the elevation angle, a greater number of computational nodes on the ground surface are covered. We confirm that WDC has an enhanced computa-tional speed when using this antenna. WDC with twelve threads achieves 550% acceleration in comparison with the case of one thread.
