Research On High-gain Multi-beam Microstrip Array Antenna Based On Mutual Coupling Reduction Between Closely Spaced Elements

With the rapid development of wireless communication technology and the continuous improvement ofpeople’s living standard, portable mobile devices are becoming more and more common. This brings greatconvenience to our life, but also leads to more complicated electromagnetic circumstance. A portablehigh-gain multi-beam wideband microstrip antenna array is urgently needed in the work of informationsecurity.Forcing issues on mutual coupling between array elements and the design of feed network for themulti-beam antenna which need to be solved in the design of the microstrip antenna array, an in-depth researchwas carried out. For the mutual coupling reduction between closely spaced array elements on the commonground, a novel idea is put forward and validated. Based on this idea, high-gain wideband array elements withmutual coupling reduction are designed. For the design of feed network which is used for multi-beam antennas,a new method on differential phase shifter is proposed. It reduces the difficulty and the work of numericalcalculation, when designing the feed network for multi-beam antenna. Based on this method and Butler matrix,a feed network for multi-beam antenna is designed. Finally, based on high-gain wideband array elements withmutual coupling reduction and feed network for multi-beam antenna, a portable high-gain multi-beamwideband microstrip antenna array is designed and measured. Measured results show that the four-beamantenna array operates at2GHz with20%bandwith. The size of the antenna array is just45cm*28cm. Thegain is more than15dBi within the working frequency band and the peak gain is closed to17dBi. Measuredresults agree well with simulation results and all indicators meet the design requirements completely.The main innovation of this paper are as follow:1、A novel idea is put forward for the mutual coupling reduction between closely spaced array elementswhich is parallel to each other on the common ground. Based on this idea, three kinds of array elements withmutual coupling reduction are designed. One of them based on two CPW which can introduce current to offsetcoupling has a good performance. Finally, combining mutual-coupling-reduction array elements withhigh-gain wideband array elements, high-gain wideband array elements with mutual coupling reduction aredesigned2、A new method on differential Phase Shifter is proposed. It reduces the difficulty and the work ofnumerical calculation, when designing the feed network for multi-beam antenna. Based on this method andButler matrix, a feed network with high performance for multi-beam antenna is designed.3、Based on high-gain wideband array elements with mutual coupling reduction and feed network formulti-beam antenna, a portable high-gain multi-beam wideband microstrip antenna array is designed.