Ray Tracing Analysis of Propagation.pdf

Ray Tracing Analysis of Propagation Characteristics in Tunnels Including I Transmitting Antenna Kazuhiro FUJIMORI Hiroyuki ARAI Division of Electrical and Computer Engineering, Yokohama National University, Yokohama, 240, Japan E-mail: fujimoriQarailab.dnj.ynu.ac.jp 1 Introduction For the communication system inside tunnels, the propagation charac- teristics of radio waves have been reported. The communication system of leaky coaxial cable has a large transmission loss in high frequency range, and the novel system using the optical fiber and the flat antenna is pro- posed. The advantage of this system is free from the transmission loss due to the optical fiber, however, the cost of E/O and O/E units are ex- pensive. To overcome this difficulty,it is required that a coverage area of one antenna should be maximized. Then, it is necessary to investigate the