Study Of Near-field Measurement Methods For The Determination Of The Scattering Characteristics Of The Targets

Near-field measurement technique is an important method in the research field ofscattering characteristics of targets at home and abroad, which has a series ofadvantages such as high measurement precision, large information quantity obtained,all-weather operation, short measurement distance and easy implementation inanechoic chamber etc. By means of the method of combining theoretical analysis withcomputer simulation, near-field measurement methods for the determination of thescattering characteristics of the targets are studied in this thesis. The main contents areas follows:Firstly, the method of bistatic planar near-field scattering measurements is studied.With the infinitely long ideal conductor cylinder as target to be measured, this methodis computer simulated. The scattered near-field data are processed by the weightingmethod of cosine window function, the parameters of which are optimized by GeneticAlgorithm (GA). The calculation results show that truncation errors caused by finitescan plane can be effectively reduced by the near-field data processing method basedon cosine window function with the parameters optimized by GA.Secondly, the method of radar imaging is studied, based on which an imagingmodel is built. In this imaging model, a frequency continuous wave is used as emissionsignal and a two-dimensional turntable scan is performed, for the target under test, sothat a two-dimensional matrix of field intensity can be obtained in the target imagingzone, in which radar imaging can be performed. By this method, the radar imaging ofideal scattering point targets is computer simulated. The calculation results show thatthis imaging method can perfectly reflect the strength of target scattering.Finally, the information of the scattering center of the target is extracted byimaging results. The far-field RCS of the target is extrapolated based on the principleof secondary radiation and compared with theoretical RCS. The calculation resultsprove that this method has high accuracy.