Probe Compensation Technology In Source Reconstruction Algorithm

With the rapid development of communication technology,the requirements of electronic equipment for antenna design have been stricter.The antenna measurement technology plays an important role in the process of antenna design.Modern antenna measurement technology is mainly divided into near field measurement,far field measurement and compact field measurement.Among them,near field measurement technology can be divided into two categories.One is the mainstream method that plane wave spectrum is used to expand the near field of the antenna to be tested,then FFT is used to calculate the far field of the antenna under test(AUT).Finally,the near-field to far-field transformation(NF-FF)of antenna is completed.The other is the equivalent source reconstruction method discussed in this thesis.It can obtain the antenna’s pattern without considering the credible angle and can also be used to measure the wide beam antenna.In this thesis,the source reconstruction algorithm is deeply analyzed and verified based on the equivalence principle.A set of probe compensation formula suitable for the source reconstruction algorithm base on the reciprocity theorem is proposed,and its effectiveness is proved by an example of a horn antenna.This thesis is organized as follows.The three stages of the development of antenna nearfield measurement technology,no probe compensation stage,initial exploration stage of probe compensation and application stage of probe compensation are introduced firstly.Subsequently the basic theorem of electromagnetic filed theory and the common methods of electromagnetic field numerical analysis are introduced,in which the equivalent principle,uniqueness theorem,the method of moments(MOM)and singular value decomposition(SVD)are highlighted.Then the integral equation of the planar equivalent source reconstruction algorithm without compensation is derived and transformed into a matrix equation.The near-field of horn antenna and array antenna are simulated with method of moment.The near-field amplitude and phase distribution and far-field pattern of AUT are obtained with equivalent source reconstruction algorithm,which are almost consistent with the reference value.The experimental result proves the accuracy and effectiveness of the algorithm.Since there is the problem of credible angle in the planar equivalent source reconstruction algorithm,the hexahedral equivalent source reconstruction algorithm is introduced in this thesis,and its theory is similar to the planar equivalent source reconstruction(SRC)algorithm.In the end,the horn antenna and symmetrical dipole antenna are simulated with method of moment to verify the accuracy of the hexahedral equivalent source reconstruction algorithm.The experimental result shows that the proposed method has no truncation error and is able to calculate the far-field pattern of the AUT in full space.The innovation of this thesis is the plane equivalent source reconstruction algorithm with compensation.In this algorithm,the reciprocity theorem is used to analyze the signal received by the probe in the actual antenna measurement process.Base on the equivalent principle,the integral equation with compensation is derived.Finally,the integral equation is transformed into a matrix equation,and the equivalent magnetic current is solved.Comparing to the planar equivalent source reconstruction algorithm without compensation,the proposed method obtains better results which are closer to the reference value.The experiment shows that the proposed probe compensation algorithm is effective.