A Large Span Beamforming Array Antenna with Cosecant Squared Pattern for Mobile Communication Application in Railway Environments

A 16-element microstrip patch antenna array with beamforming radiation pattern is proposed for railway mobile communication applications. Four antenna arrays with different beam angles are designed first, and their beams can be superimposed to achieve a cosecant squared pattern. Then, the four arrays are mapped into a composite antenna array. The feeding network of the composite array is designed based on the amplitudes and phases obtained by superimposing those of the four arrays in a weighted way. The simulated results show that the impedance bandwidth ( |S<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</inf>|< -10 dB) of the antenna array is between 3.45 - 3.55 GHz and the peak gain is 13.8 dBi. The designed radiation pattern is consistent with the desired cosecant squared pattern very well, and an angular beamforming range of 60° can be achieved at 3.5 GHz, which proves the effectiveness of the beamforming method in this paper.