国際プロジェクト実習　【ドイツ】
DLR Microwaves and Radar Institute Oberpfaffenhofen
Budhaditya PYNE　[D3]
(Graduate School of Engineering, Department of Electrical Engineering and Information Systems)

　My PhD research at JAXA concerns the design and development of the antenna panel waveguide feeder network for a X-band space-borne Synthetic Aperture Radar (SAR) sensor capable of 1-meter imagery, compatible with a 100kg-class small satellite for the upcoming MicroX-SAR Mission, for the purpose of continuous Earth Observation for the monitoring of natural disasters in South-East Asia. During my PhD, I have accumulated experience in antenna design simulations using the Ansys HFSS software, and in the measurement of fabricated antenna patterns in Anechoic Chamber for passive slot-array antennas. Practical points of interest for SAR system performance evaluation are thermo-elastic surface distortions for space-borne antennas which cannot be easily taken into account in commercial software. Furthermore, as the antenna size increases, the long-time taken by software to compute antenna patterns make them inefficient to use for efficient performance evaluation from a Mission Design perspective.
　Before I did my IP, I had no prior experience with SAR Mission design or Reflector Antennas or Python, and had very limited experience in SAR Signal Processing. Thus, I decided to do my IP under the supervision of Dr. Marc Rodriguez Cassola, Head of the SAR Missions Group in DLR Microwaves and Radar Institute, Oberpfaffenhofen, Germany, since his group has a proven track-record of conducting high-impact research. I was very warmly welcomed the Head of the Institute Dr. Alberto Moreira, Dr. Cassola and his group as one of their own and I immediately realized I could not have chosen a better place for my IP. After a very fruitful discussion with Dr. Cassola, I was assigned to work with my colleague Mr. Jalal Matar on a Python-based Antenna Class Pattern Computation Module for DLR’s End-to-End Simulator, which could quickly (within several seconds) and accurately (less than 0.1 dB error) compute antenna patterns for non-ideal planar arrays and reflectors considering thermo-elastic antenna surface distortions combining Geometrical Optics and Fast Fourier Transforms by our proposed beam-center approach. It was a very challenging task to do in just four months, especially since I was not previously acquainted with Python programming, and the electromagnetic phenomenon in reflector antennas were much more complicated than slot-arrays. The work-culture in Germany, having harsh restrictions on overtime work, meant I needed to significantly increase my working efficiency since, as a Guest Scientist, I had no access to my workplace on weekends. However, Mr. Matar, being a very good programmer, helped me get acquainted with Python swiftly and along with Dr. Cassola’s exceptional vision and guidance, by virtue of great teamwork, we managed to meet our goals within our desired timeframe. I learnt several new things during my IP including team-work and I was very pleased to receive highly encouraging and positive feedback following my final presentation in DLR. A journal paper is being drafted based on IP research for publication in IEEE Geoscience and Remote Sensing Letters. A European patent application is also expected to be filed following further development of the Python Pattern Tool. I am very grateful to Dr. Cassola and I would love to work with him and his group again in future. I had the opportunity to attend several workshops and invited talks from academia and industry during my stay in DLR.
　I was very lucky to have an amazing landlady, who was very kind and made me feel like a family member during my stay. I celebrated Christmas, Easter and also my birthday with her, an experience I will always cherish. Being not allowed to work on weekends meant I could explore beautiful Bavaria and enjoy its culture. Besides Munich, being very conveniently geographically located and transportation costs being much cheaper than Japan, I went to Cologne, Bonn, Berlin, Zugspitze, Vienna, Prague, Zurich, Bolzano and Obergurgl for weekend trips, and I thoroughly enjoyed exploring Europe, making new friends and always came back refreshed for working on Mondays. In particular, I really enjoyed my visit to the Spaceplane Buran Exhibit in Technik Museum Speyer with my Russian friend, who is an astronomer.
　My advice to GSDM students would be plan your IP in advance and assign top priority to time allocation when handling ambitious projects, and always keep an eye open for networking, which is of critical importance for your career. You should never feel content just getting accepted; instead strive to perform well to be of value to the group you are working with. You should try to interact as much as possible with your colleagues; don’t hesitate to ask questions and opinions, professional feedback and suggestions are priceless. Finally, try to make the most of life outside research during weekends. Make new friends, explore your surroundings; enjoy a different lifestyle and culture; IP abroad opens up an abundance of new opportunities not possible within Japan.