Analysis And Resarch Of The Far-field Antenna Measurement System

In the far-field antenna measurement system, the traditional way of erecting antennas,low degree of automation, time-consuming manual processes, resulting in a measurement of inefficiency, so need to study the efficiency of new technical equipment measurement systems, this measurement system in an anechoic chamber can be achieved in various types of 0.5GHz ~ 40 GHz radar antenna and radar equipment against the far field pattern, gain and other parameters to realize the accurate measurement of the overall performance of the radar. After the automatic antenna measurement system through computer programming,and then complete the setting emission source frequency, output power, operating mode and other parameters, while controlling the rotation of each axis turntable, emission source emits electromagnetic waves emitted by an antenna, the signal arrives at the receiving antenna, due to space loss of signal energy needed to raise the signal through whispered noise amplifier power, reach vector network analyzer by high-frequency signal line, a signal acquisition time approach angle is displayed.In this paper, the basic method for antenna measurements are also carried out research,to ensure indoor far-field distance R = 35 m, under 0.5Hz ~ 40 GHz frequency band, the system uses a rotating antenna pattern mapping method, although well calibrated standard antenna gain values, we indoors by building three-antenna measurement system verification standard antenna gain, antenna installation height H is 2.6m, and the spacing between the transmitting and receiving antennas R is 12.68 m, laser alignment, meet the far-field measurement distance to good effect, and subsequently use comparative method to measure the gain of the antenna under test in automated measurement systems. Then, the environment of the system, the composition of the various subsystems and their respective functions in-depth research, as well as implementation of software functionality gives detailed instructions.Far-field measurement system for automated error analysis of the face pattern and gain errors, pattern analysis of three aspects of the measurement error from the measurement distance and angle measurement environment, mainly on the angle measurement analysis to calculate the percentage of relative error and gain error from the polarization mismatch,impedance mismatch, and aspects of the coupling phase center receiving antenna does not overlap the analytical error, mainly limited to measuring distance error introduced study,and relative error obtained gain antenna size, operating frequency and darkroom measuring the relationship between pitch curve.This design study of the log-periodic dipole antenna design 0.2GHz ~ 2GHz band log-periodic antenna, use HFSS13.0 modeling, simulation and analysis of the model calculated the gain and pattern, and in the measurement system the actual measured values are compared, the results in line with expectations vision.