Study Of Vector Antenna And Its Application In Wide Angle Scanning Array

A novel pattern reconfigurable element antenna with wide beam width is proposed in combination with the pattern reconfigurable technology for improving the wide angle scanning specifications,which is based on the omnidirectional radiation property of vector antenna and its composing elements.A method of dividing region for wide angle scanning is also proposed using the characteristics of the four reconfigurable endfire modes of the Alford loop antenna.The main research content of this paper can be divided into the following three parts.First,the farfield radiation pattern of 2D and 3D electric dipole vector antenna is analysed by the method of farfield superposition and current superposition,respectively.The analysis results show that electric dipole vector antenna can be equivalent to a single dipole whose oriention is controlled by the exciting amplitude of the composing elements.And the radiation pattern of the electric dipole vector antenna is simulated and verified by CST software.Then,the pattern reconfigurable Alford loop antenna with four endfire modes are proposed,which are referred as Up radiation mode,Down radiation mode,Left radiation mode and Right radiation mode,by loading four PIN diodes on the original Alford loop antenna.Each endfire mode can provide wide angle beam and the 3dB beam width in E plane and H plane is 840 and 196°,respectively.The pattern reconfigurable Alford loop is simulated with HFSS software.The proposed antenna is manufactured and measured.The test results are consistent with the simulation results.Finally,the beam scanning property of uniform linear array and uniform planar array composed of the proposed antenna with R radiation mode are analysed and simulated.The planar array composed of the proposed antenna with R radiation mode is able to scan in the region of 45°<θ<135°,-45°<φ<45°.A method of dividing region for wide angle scanning is presented by the four reconfigurable endfire modes of the proposed antenna.Simulation results show that gain loss is less than 3.5dB and beam pointing error is less than 30 at θ = 90°.The antenna gives a way to solve the wide angle scanning problems.