The Cable Phase Difference Detection of Very High Frequency (VHF) Antenna Array Based on Ad8302

Abstract

Among the very high frequency antenna measurement methods used in radio astronomical observation, phase measurement technology is one of vital importance in the process of data acceptance and disposal, for it has great priority in antenna pattern and accuracy in tracking radio source at different region. Particularly, affected by the natural environment, cable phase error is produced, thus the traditional measurement method that depends on different environmental experience value to correct phase error is complex and inaccurate. According to the principle of low frequency antenna array phase measurement, this paper suggests a better method, which uses AD8302 to transfer the two calibration source signal phase difference of the receiver and transfer feeder to the corresponding direct voltage, then realizes single channel AD sampling with 12 bits quantization accuracy, finally does the error analysis and correction to achieve phase error correction. Through testing the precision of phase error of the cable given by the system under measuring conditions of low frequency (2MHz), high frequency (300MHz), etc. We can prove the system has a very high reliability, thus could be widely used in related antenna array error correction and cable error measurement.