Design Of Beamforming Antenna Array For Mine Pit Wireless Communication System

The article is a selected topic research according to the scientific research item, the paper aim to design and realize a method of beamforming antenna array which applies in the mine pit communications system.The beamforming antenna array used in mine pit communication system should have characteristics of small size, light weight,10% of the relative bandwidth,30°of maximum aspect angles, lOdB of the gain.The microstrip antennas have some principal advantages, such as light weight, small size, low profile and so on. But the ordinary microstrip patch antenna's relative bandwidth approximately is only about 5%, which cannot satisfy the mine pit communications system. Therefore, the article selects dual-layer microstrip patch structure as element of antenna array. Microstrip patch antenna is preliminarily designed according to the microstrip antennas basic design method. Based on this, the Ansoft HFSS software is used to optimize the antenna. The final result shows that the impedance bandwidth (VSWR<1.5) has reached up to 10% which satisfied the requests of the beamforming antenna.In order to achieve the requirements of high gain and the biggest aspect angles for 30°, the article used the dual-layer patch antenna as the element of the antenna array, combining the theoretical calculation and the HFSS software simulation, a four line array is designed. The simulation result indicated that the maximum aspect angle of this antenna array achieved 31°, the gain is 12.8dB, which can satisfy the request.This article has used the Wilkinson divider to design feed network for the antenna array, according to the basic design theory of Wilkinson divider, equal divider and 2:1 unequal microstrip divider have been designed respectively. The equal divider, unequal divider and microstrip extend line form the whole feed network.The article also has designed a thin radome made of plexiglass. Finally, simulated the antenna array, feed network and the antenna radome. Based on the result, the entire antenna system has been manufactured and tested as well. The measured result shows that the impedance bandwidth(VSWR<1.5)of the antenna array is 15%, the gain is 11.09dB, the maximum aspect angle is 31°, which satisfied the design requirement.