Kouhei Suzaki

Wave propagation simulations for considering the installation of the maritime mobile satellite communication antennas

In maritime mobile satellite communications, received satellite signal level varies due to direction and motion of a ship. Then sometimes the communications are interrupted, because the receiving satellite signal level decreases when the ships body shadows the antenna. Thus it is important to evaluate how qualities of satellite communications vary during ship operations. However, precise temporal level fluctuations during ship movement are not yet studied. In this paper, to evaluate temporal variances of receiving satellite signal level of the ship in motion, modeling and numerical simulations were performed with considering the effect that the ships body shadows the antennas. Effects of pitching, rolling and yawing were taken into accounting the calculations. In addition, electric field levels around the ship were estimated when transmitting antennas are in proximity to the ship body.

A novel earth station antenna concept for Ku-band mobile satellite communication systems -Distributed array antenna and key technologies-

This paper proposes a novel ESV (Earth-Station on Vessel) antenna system, the concept of the distributed array antenna (DAA) system, and its key technologies. The performance of our DAA system’s EIRP and G/T increase in proportion to the number of tracking antenna. Since the appropriate phase control of each transmitted signal is essential to maintain spatially in-phase combing, two phase compensation techniques for the realization of the DAA system are proposed and verified.

Experimental verification of high gain ESV employing Distributed Array Antenna technology

An experiment is conducted to verify that the Distributed Array Antenna (DAA) technology[1] can achieve high antenna gain. DAA consists of several small tracking antennas with improved antenna gain. Since the appropriate phase control of each transmitted signal is essential to maintain in-phase combining at the satellite antenna, two phase compensation techniques are proposed. We implement these techniques in a DAA and test it. The results confirm a gain increase of 2.94 dB by using 2 antennas.