The Characteristics of Ultra wide band antenna in decimeter and centimeter wavelength used for Mingantu Spectral Radioheliograph (MUSER)
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The Characteristics of Ultra wide band antenna in decimeter and centimeter wavelength used for Mingantu Spectral Radioheliograph (MUSER)
Tue, 10/03/2020 - 14:00 to 15:00
Location:
Speaker:
Dr Sha Li
Affiliation:
Solar Activity of Chinese Academy of Sciences
Synopsis:
Mingantu Spectral Radioheliograph (MUSER) is an aperture-synthesis telescope observing the Sun in Inner Mongolia. It contains 100 reflector antennas which constitute two arrays MUSER-I(0.4-2GHz) and MUSER-II(2-15GHz) respectively. In order to obtain ultra wide-band performance, the cascaded folded dipoles are used in this feed. Also, a wide-band 3dB hybrid is added at the output ports of the feed to get circularly polarized signals coming from the Sun. The feed has perfect characteristics of about 10 dBi gain, low voltage standing wave ratio, fixed phase center location and constant beam width in the operating frequencies. Through calculating the combinations of two orthogonal polarizations at each antenna, the polarization state of the wave is measured and gives a differential instrumental delay between two data channels. The error between the original polarization degree of the Sun and the observed polarization degree is also measured for cross-polarized delay, some solar radio images are also demonstrated, they have good match comparing with images from other telescopes.
Biography:
Sha Li was born in Xi’an, China in 1984, she received the B.S. and M.S. degree in Electromagnetic and Microwave technology from Xidian University, Xi’an, China, in 2006 and 2009 respectively, and the PhD degree in Astronomical techniques and methods from University of Chinese Academy of Sciences in 2015. She joined the National Astronomical Observatories, Chinese Academy of Sciences as an assistant engineer in 2009 and currently she is an Engineer in the Key Laboratory of Solar Activity of Chinese Academy of Sciences. In this lab, different types of telescopes observe the Sun and get large storage data every day. Her research interests include antenna theory, design, simulation and measurement in centimeter and decimeter wavelength, as well as the solar radio data analysis.