Simple satellite-tracking stacked patch array antenna for mobile communications experiments aiming at ETS-VIII applications

The Japan Aerospace Exploration Agency (JAXA) plans to launch a geostationary satellite called Engineering Test Satellite-VIII (ETS-VIII) in 2004. In the paper, the feasibility of reaching a relatively high value of gain at low elevation angle by use of a simple left-handed circularly polarised four-element stacked patch array antenna for mobile satellite communications in the S-band frequency aiming at ETS-VIII applications is discussed. The characteristics of this antenna are confirmed by two numerical methods (the method of moments and the finite element method) and by measurements. Furthermore, the influence of the finite size of the ground plane was analysed using of the finite element method. Both numerical analyses and measurements are presented. In addition, the operation of beam-switching is experimentally confirmed. It is revealed that, by properly feeding the patches constituting the antenna, for an elevation El=48° (θ=42°) in Tokyo, four beams are created in the conical-cut direction at azimuth Az=6°, 96°, 190°, and 276°. The gain reached more than 6.5 dBic on the whole azimuthal range, with an axial ratio less than 3 dB.