Control System Of Near Far Field Antenna Measurement

With the development of mobile information technology,it demands more antennas of high qualities and high accuracy.Antenna measurement technology and system develop fast,and is a key technical backstopping in the antenna design,production,and debugging.The early antenna measurement system has a low degree of autonomy,which leads to the low efficiency of the antenna measurement and low rate of spreading.As computer technology and automatic control technology develop in recent years,high efficiency and high precision has become one of the focuses in the field of antenna measurement.In some developed countries,the development of high efficiency and high precision measurement system has been studied for many years and has been put into use,but researches in this technology started just now in our country.According to a certain production practice for a company,we design a set of planar near field antenna measurement system of high precision and high efficiency in this paper.The system will be used in the microwave anechoic chamber,which can be used for the near field measurement of the slot antenna,the interrogation antenna and some conventional antennas,and can be used to measure small aperture antennas in the far field with the measurement frequency range of 1.2-40 GHz.The near far field antenna measurement system we designed in this paper bases on industrial computer as the core,which can control vector network analyzer initialize the related parameters,and control the PMAC motion controller drives scanning plane or scanning cylindrical at the same time,so we can get tangent field data and sampling point coordinates.Finally,the system uses the data processing software provided by the system to get the far field characteristics of the antenna to be measured.Firstly,we describe the basic theory of antenna measurement,the basic antenna parameters and the measurement methods of each parameter in this paper,which provide technology support for the system design and data processing software in the next part.Secondly,we introduce the hardware of antenna near field measurement system briefly,including scanner,turntable,RF,CNC servo subsystem,mainly analyze scanning frame structure,error and the design of the axis of rotation,and do the safety design of mechanical motion system which can ensure the system operate reliably and safely..Then,this paper introduces the motion control principle of PMAC motion controller and the design for the control system.Finally,use Delphi and MATLAB language to compile a set of data processing software.PMAC has the characteristics of high precision and multi-function,and is compatible with the most measurement instruments and equipment in market,so the near field and far field antenna measurements system use PMAC programmable multi axis motion controller as the servo controller of the antenna measurement system,which make the mechanical error of the antenna measurement system be limited in 0.05 mm.Compared with the traditional antenna measurement system,the accuracy of the measurement system we designed is higher.The control software compiled in the paper and data processing software can meet the design requirements of the system,and the system is convenient to operate and the interface is artistic.But the error of antenna measurement is not analyzed in this paper,so the error analysis of antenna measurement can be carried out for the following work.Now,the antenna measurement system we designed has been built and put into use.The practice show that the high accuracy and high performance antenna measurement system described in this paper meets the requirements of the company and has good practical value.