Research On The Accuracy Of Spherical Near-field And Far-field Transformation Algorithm

Today’s world has higher requirements for Internet technology and communication technology.The performance of the antenna is developing in the direction of high-gain and ultra-broadband.As the operating frequency of the antenna becomes higher and higher,the requirements for the antenna measurement technology also increase.As an accurate antenna measurement technology,spherical near field measurement technology has attracted much attention.It can measure various types of antennas without considering the advantages of truncation error,making spherical near field measurement technology has become one of the most popular measurement technologies.This topic revolves around the spherical nearfield measurement technology,based on the spherical wave mode expansion technology,pays attention to the accuracy of the traditional spherical near-field measurement technology and the phaseless spherical near-field measurement technology,and gives reasonable parameters and solutions.The specific research contents are as follows:1.Based on the theory of spherical wave mode expansion,the correctness of the spherical near-field measurement algorithm is verified by the simulation of the half-wave oscillator array antenna.The effects of the probe measurement distance and the spherical measurement radius on the measurement accuracy of the spherical near-field are analyzed.And summarize the relationship between sampling interval and sampling radius,and propose reasonable sampling interval and sampling radius.2.Based on the theory of spherical wave mode expansion,the theory of double spherical phaseless near-field measurement is deduced,and the correctness of the algorithm is verified by the horn antenna simulated by HFSS.It is analyzed that when the antenna frequency is high,the appropriate sampling interval will become very small,and the workload of sampling will be very large.This subject uses cubic spline interpolation algorithm to interpolate the sampling distance,which effectively reduces the sampling distance and improves the accuracy of the algorithm.3.The phaseless spherical near-far field transformation algorithm is actually an alternate projection algorithm.The sensitivity of the phaseless spherical near-field measurement algorithm to the initial phase is analyzed.By comparing the random initial phase and the initial phase based on the aperture shape,this subject judges whether the algorithm can effectively restore the far-field pattern,and verifies the sensitivity of the phaseless spherical near-far field transformation algorithm to the initial phase.The robustness of the double spherical phaseless near-far field transformation algorithm to the beam pointing of the array antenna is also verified,and its good robustness is more suitable for the measurement of the array antenna.