5:15 PM - 7:15 PM
[PCG20-P02] Development of a meter wave band antenna feed for the Iitate planetary radio telescope IPRT
Keywords:development, grand-based observation, antenna, meter-wave band
The Planetary Plasma and Atmospheric Research Center, Tohoku University has been operating the Iitate Planetary Radio Telescope:IPRT with a physical aperture area of just over 1000 m^2 since 2001, and is currently developing a feed system to achieve higher sensitivity in a wider bandwidth. The current IPRT receiving system is equipped with a narrow-band high-sensitivity observation system centered on 325 MHz (& 650MHz: under development) and an independent broadband solar radio spectrum observation system targeting the 100-500 MHz band, but the latter has a weak point in terms of sensitivity. With the recent renewal (e.g. uGMRT) and development (e.g. SKA) of large radio instruments, it has become important to improve the efficiency of broadband feeds in order to promote low-frequency VLBI observations, which are expected to expand further in the future. Therefore our group has started to develop a new feed system for the 100-700 MHz band, aiming at higher efficiency by integrating feeds for high-sensitivity and broadband observations (target: 60% or more for the 325 and 650 MHz bands, and 40% or more for all frequency bands).
We have been studying the design using the electromagnetic field analysis software FEKO, using a self-compensating 4-arm sinuous antenna (c.f. de Villiers, 2017) as a model case, which has been reported as a feed for SKA-MID band-1, and have found that a pyramidal shape with ease of fabrication and a frequency range of 50 MHz can be used for the SKA-MID band-1. As a result, we were able to find a solution that is expected to have an aperture efficiency of 50% or higher in the entire frequency band with a pyramidal shape that is easy to fabricate. For the purpose of verification using actual equipment, a 1/4-scale model was fabricated and its beam characteristics were evaluated in the anechoic chamber of the RISH, Kyoto University. In late December 2024, the 1/4-scale model was installed in the IPRT and the irradiation efficiency and aperture efficiency were actually measured. As the result, it was confirmed that the aperture efficiency at 400-1100MHz would be achieved to be more than 40%. Currently, the actual fabrication method and the transmission and amplification system are being investigated with the aim of completion in FY2025.
In the presentation, details of the design and the contents and results of the evaluation and measurement using a 1/4-scale model will be presented.
We have been studying the design using the electromagnetic field analysis software FEKO, using a self-compensating 4-arm sinuous antenna (c.f. de Villiers, 2017) as a model case, which has been reported as a feed for SKA-MID band-1, and have found that a pyramidal shape with ease of fabrication and a frequency range of 50 MHz can be used for the SKA-MID band-1. As a result, we were able to find a solution that is expected to have an aperture efficiency of 50% or higher in the entire frequency band with a pyramidal shape that is easy to fabricate. For the purpose of verification using actual equipment, a 1/4-scale model was fabricated and its beam characteristics were evaluated in the anechoic chamber of the RISH, Kyoto University. In late December 2024, the 1/4-scale model was installed in the IPRT and the irradiation efficiency and aperture efficiency were actually measured. As the result, it was confirmed that the aperture efficiency at 400-1100MHz would be achieved to be more than 40%. Currently, the actual fabrication method and the transmission and amplification system are being investigated with the aim of completion in FY2025.
In the presentation, details of the design and the contents and results of the evaluation and measurement using a 1/4-scale model will be presented.