Research On Pattern Reconfigurable Antenna And The Application In Phased Array

The pattern reconfigurable antenna possesses the functions of dynamic beam switching and sense finding,so that the main beam can be focused on the desired direction by switching the beam to achieve spatial diversity.Pattern reconfigurable antennas including phased array are widely used in complex wireless environments,such as cellular and satellite communications,vehicle communications,and wireless local area networks.Based on the application requirements of pattern reconfigurable antenna,this paper mainly studies multi-beam reconfigurable antenna,and finally combines pattern reconfigurable technology with phased array to improve the wide-angle scanning performance of array.The details are as follows:1.A pattern reconfigurable planar end-fire antenna based on windmill-shape patch is proposed.By adding a shorting post at the end of the windmill-shape patch branch to destroy the distribution of original annular current,the end-fire pattern with high front to back ratio is obtained.Then,shorting posts are added to the ends of the four branches of the antenna,and PIN diodes are used to connect the shorting post and the ground.Finally,a simple bias circuit is designed to realize the switch of four radiation states by controlling the on-off of four PIN diodes.The results of measurement show that the reflection coefficients of the four radiation states are less than-10 dB in the 2.4-2.6 GHz band,and the four radiation states are end-fire patterns in four directions respectively.2.A pattern reconfigurable antenna based on stacked circular patch is proposed.Firstly,a central probe is used to excite the circular patch and a shorting post is added to excite the TM11 mode.In order to realize the reconfiguration,shorting posts are used in four directions of the circular patch,and PIN diode is used to connect the shorting post and the ground.By switching the on-off of the PIN diodes to change the current direction of the circular patch.The TM21 mode is then excited by a probe at the edge of another circular patch.The measurement results show that in the 2.48-2.52 GHz band,the reflectioncoefficient of the antenna in four states is less than-10 dB,and the patterns of four radiation states are tilted towards four directions respectively,the tilt angle is 30°,and the gain is up to 5.87dBi.3.A pattern reconfigurable antenna based on stacked rectangular patch is proposed,and a 5*1 1D linear phase-controlled array is constructed based on the unit.First,the odd mode and even mode of the rectangular shorting patch antenna are excited by using central excitation and differential excitation respectively.The patterns of the two modes are mixed in E-plane to obtain the inclined pattern.In order to realize reconfiguration,a reconfigurable feed network is designed at the bottom of the ground.In the 4.95-5.05 GHz band,the patterns of the antenna unit on two states are tilted in two directions respectively.In the E-plane of the upper half space,the main beam of 5*1 array can scan from-60° to 60° with a gain fluctuation of 1.7 dB,and and achieves a 3 dB beam-width coverage from-82° to 82°.