Research On Characteristics Of Beam Switching Holographic Antenna Based On Amplitude Weighting

With the development of modern communication technology,the beam switching antenna has received extensive attention as a low-cost,high-performance smart antenna that can achieve point-to-multipoint radio wave coverage.Holographic theory is developed from optical imaging technology.When the reference wave radiated by the feed source and target radiation wave are determined,the holographic interference fringe pattern can be formed.When the same reference wave is used to excite the holographic antenna with the corresponding interference pattern,the target beam can be restored.Therefore,when the amplitude and phase(interference pattern)of the antenna element are adjusted,the beam direction of the antenna can be adjusted.The holographic antenna technology based on amplitude weighting is a method to change beam direction of the antenna only by changing excitation amplitude of the unit without changing the phase.Aiming at the application requirements of point-to-multipoint communication,this paper studies and designs the beam-switching holographic antenna loaded with PIN diodes based on amplitude weighting.The work and innovation of this paper mainly include the following aspects:1.The beam switching one-dimensional holographic antennas based on two transmission structures are proposed and designed.The first one is a one-dimensional antenna using the oval slot element based on the microstrip line,and the second is a one-dimensional antenna using the inverted C-shaped slot element based on the substrate integrated waveguide.And,their radiation characteristics are analyzed.The research results show that both antennas can realize beam switching in one-dimensional space.For the needs of antenna processing,the diode’s DC bias network and the second antenna are integrated,and an antenna integration structure loaded with DC bias network is designed.The integrated antenna is actually processed and tested,the experimental results are basically consistent with the simulation,and the beam switching function of the designed antenna is verified.2.A beam switching quasi-two-dimensional antenna array is proposed and designed.First,a 4×4 Butler matrix based on substrate-integrated waveguide operating at 5.8 GHz is designed as the feed network of the array,and then it is integrated with a 1×4 array composed of one-dimensional holographic antennas based on substrate-integrated waveguide.Thereby the antenna array can realize beam switching in quasi-two-dimensional space.The radiation characteristic of the array is analyzed.And the effectiveness of the design is shown.Then the designed linear integrated array is miniaturized and folded.The feeding network is folded to the back of the array element antenna,and the array element antenna is fed by slot coupling.By studying the radiation characteristic of the folded antenna,it is shown that the antenna can still achieve beam switching in quasi-two-dimensional space while being miniaturized.3.Based on the theory of two-dimensional holography,a two-dimensional holographic square array antenna operating at 13 GHz is designed.Firstly,a U-shaped holographic element suitable for two-dimensional antenna is designed and its resonance characteristic is analyzed.Secondly,the effects of the size of the dielectric plate,the number and spacing of the array elements,and the coding rule on the impedance matching and radiation characteristic of the array are analyzed.Finally,a two-dimensional holographic antenna array based on parallel plate waveguide is designed,and its reflection and radiation characteristic are analyzed.The results show that the antenna can realize beam switching in two-dimensional space.