Phased Array Antenna Measurement And Calibration Technique And Its Error Analysis

With the requirements of military communication confrontation and civil communication getting higher and higher,phased array technology has become the most important antenna technology.The theoretical study of phased array antenna began very early.The topics of broadband,wide angle,circularly polarization and array synthesis have been studied by many scholars.Their work is very important for phased array design.However,phased array calibration,which influences directly whether the performance of phased array is as well as designed,has not been studied as sufficiently as phased array design in engineering.Based on this,this thesis has carried on in-depth theory and engineering research of the phased array calibration and the related measurement technology.The main work is summarized as follows.1.We establish a general understanding method of phased array calibration and measurement,illustrate the relationship between calibration and measurement and give the real physical model and abstract mathematical model during calibration procedure.The real physical model characterizes the relationship between the actual measured data and the physical quantity to be measured during the calibration measurement.The abstract mathematical model embodies the understanding of this relationship in the calibration measurement process.Based on this,we illustrate the error model of the calibration measurement,classify the calibration methods,and analyze the calibration errors for the linear and non-linear models,respectively.2.We have analyzed the linear point measurement method,described its real physical model and established the abstract mathematical model.Linear point measurement methods need to constantly change the array excitations,which is usually realized by setting the phase of array excitation.It is proved in this thesis that the phase settings decide the characteristic of the data processing matrix and then decide the complexity and accuracy of the measurement method.We propose that the phase settings decided by Hadamard Matrices are extremely good,verify the influence of every fact to the measurement accuracy with detailed simulations and prove the reliability and correctness of this method with experiment.3.We have carried on the theoretical analysis to the linear surface measurement method,described its real physical model and established the abstract mathematical model.The linear surface measurement method is specifically analyzed according to the cases of the uniform circular and linear arrays.It is proved theoretically that the field selection,distribution,number and distance to array surface of measurement points and antenna type are all influence the characteristic of data processing matrix and then the measurement accuracy.The real array excitations during measurement also influence the measurement accuracy.The theoretical analysis results are verified with simulation analysis of the uniform circular array and linear array.The reliability and correctness of this method is verified with the experiment of a linear array.4.We have studied the non-linear measurement method and turned the non-linear method into the linear method and simple non-linear equations by taking the inner products of the physical quantities to be measured as the middle parameters.It is concluded that the array phase setting,the grouping method and the real array excitation influence the complexity and accuracy of the non-linear method according to the error analysis of non-linear equations and the linear methods.Based on this,we have proposed the measurement method with minimum measurement times,put the traditional rotating electric vector method into our theory and verified our theory with simulations and experiments.5.We have described the online calibration method and the fast calibration method in practical application and carried on the theoretical analysis of the relationship between the feed system and the calibration methods.It is proved that almost all the calibration methods actually have a default assumption on the isolation of the feed system or the isolation of the array ports.The influence of the assumption on the calibrations methods is also analyzed.