Active Phased Array Antennas have attracted attention for use as hopping spot beam antennas that might be used as electronically controllable onboard satellite antennas. It is difficult to monitor the output of each amplifier at its output port directly, so the rotating element electric field vector method which has been already adopted as a means of determining the health of the transmitter and receiver modules in the onboard synthetic aperture radar is also effective for Active Phase Array

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... ennas. However, the difference between relative amplitude and phase values calculated using measurement data and those predicted values often becomes large due to the radio propagation characteristics change, signal level change in the satellite, satellite position and attitude determination errors and so on. This paper describes health check experiment of antenna elements on WINDS featuring two stations simultaneous measurement to improve the predicted relative values. It also describes that the phase difference of the RX antenna was greatly decreased, and the number of RX antenna elements whose phase difference is within 5.625 degrees was increased at two stations simultaneous measurement as compared with the results at one station measurement.