The Design Of Antenna Automatic Measurement System Based On Spherical Near-Field Measurement

As a king of near-field measurement technique,spherical near-field measurement technique has lots of advantages campared with other measurement techniques.It has been the measurement technique which is often used at home and abroad.The design of antenna automatic measurement system based on spherical near-field measurement has great significance.Under the support of the school teaching reform project,the research and design of the antenna automatic measurement system based on spherical near-field measurement is carried out.The main works as follow:(1)At first,the calculation part of the formula without probe correction is simplified.Then the simplified formula without probe correction is programmed.On the other hand,the near field data and far field data of a rectangular horn antenna can be got by simulating with the simulation software HFSS.The far field data is compared with the data which is converted to far field from near field by non-probe correction program.The results keep conformity.(2)The calculation part of the formula with probe correction is simplified.Then the simplified formula with probe correction is programmed.The open-ended rectangular waveguide whose incentive mode is the TE10 mode is used as the probe and a open-ended rectangular waveguide is used as the antenna under test.The spherical near-field measurement with the antenna under test and the probe is simulated.The data which is transformed from obtained data by the probe correction program is compared with the simulation data.The results keep conformity.(3)The measurement system is designed.The data which is need is measured by vector network analyzer and at the same time turntable is roteted by computer.Then the measured data can be processed.Thus the measurement of the antenna is realized.The control of vector network analyzer and turntable is realized through Labview.And the near-field farfield transformation is realized through MATLAB.The converted data measured by the.measurement system is compared with the data measured in the anechoic chamber with far-field measurement.For ? = 0°,??0° and 0°?? ? 90°,the absolute error of amplitude is small,the average of the absolute error is about 3.36dB.The mean square error is about 2.71dB.For ? = 0°,? = 0° and 90° ???180°,the absolute errror of amplitude is big.