5:15 PM - 6:45 PM
[PEM16-P01] Development of the phased array antenna system for next generation solar wind observation system:design of sub-array
Keywords:solar wind, phased array antenna, radio observation
A radio wave of astronomical object can be scattered by plasma disturbances in solar wind flowing through interplanetary space. This phenomenon is called interplanetary scintillation (IPS). Nagoya University has conducted IPS observations by large radio telescopes at 327± 10 MHz. We can derive solar wind velocity and detect coronal mass ejection (CME) caused by eruptions on the solar corona by IPS observations. If IPS observation performance is improved, we expect to improve forecasting accuracy of CME arrival on Earth and further understanding of solar wind. Therefore, we develop “next generation solar wind observation system” that is capable 10 times more IPS observations than existing instruments. As the first step in the development of next generation system, we plan to develop a flat phased array antenna system with 64 sets of subarrays consisting of 16 antennas, for a total of 1024 antennas.
In this study, in order to realize this plan, we developed subarray with good impedance behavior at 327±10 MHz. As a prototype, we developed a sub-array using Yagi-Uda antennas, with enough sensitivity in the 300 MHz-360 MHz bands, on a 4 m PVC pipe. To evaluate its impedance matching, we placed 7 antennas on a PVC pipe at approximately 55 cm intervals in a room, and we measured the S11 parameter for each antenna. In this evaluation test, in order to minimize the effect of grading lobes on the directivity of array antennas, we placed each element antennas with a minimum distance spacing. The measured S11 of 6 antennas of them were improved compared their independently measured S11 value. These changes cloud be caused by the mutual coupling between antenna elements or external influences in a small indoor space. In order to develop subarrays with better impedance matching and to conduct accurate evaluation tests, we should investigate the effect of mutual coupling between antenna elements on a large place where external factors can be eliminated.
In this study, in order to realize this plan, we developed subarray with good impedance behavior at 327±10 MHz. As a prototype, we developed a sub-array using Yagi-Uda antennas, with enough sensitivity in the 300 MHz-360 MHz bands, on a 4 m PVC pipe. To evaluate its impedance matching, we placed 7 antennas on a PVC pipe at approximately 55 cm intervals in a room, and we measured the S11 parameter for each antenna. In this evaluation test, in order to minimize the effect of grading lobes on the directivity of array antennas, we placed each element antennas with a minimum distance spacing. The measured S11 of 6 antennas of them were improved compared their independently measured S11 value. These changes cloud be caused by the mutual coupling between antenna elements or external influences in a small indoor space. In order to develop subarrays with better impedance matching and to conduct accurate evaluation tests, we should investigate the effect of mutual coupling between antenna elements on a large place where external factors can be eliminated.