TY - JOUR
T1 - A new impedance matching method for an ultra-wide band and dual circularly polarised feed
AU - Li, Sha
AU - Yan, Yi Hua
AU - Wang, Wei
AU - Chen, Zhi Jun
AU - Liu, Dong Hao
AU - Zhang, Fu Shun
AU - Jeffrey, Natasha
PY - 2016
Y1 - 2016
N2 - In traditional antenna design, metal components are not placed in the central part of the antenna as they change the characteristics of near field radiation. However, we show that placing a metal ring in the centre of the strip lines, which connect the ends of folded high-frequency dipoles, does not damage the performance of the feed. Instead it significantly improves the voltage standing wave ratio of the feed whilst other performance indicators are not compromised. Thus, our findings show an excellent way of improving the wide band feed. Based on this foundation, a new circularly polarised feed for operation between 0.4 to 2 GHz is introduced for the Chinese Spectral Radioheliograph in this paper. The issue of a feed impedance matching network is investigated. By optimising the impedance matching, the performance of the feed is enhanced with respect to the previous realisations of the Eleven feed. The simulation and experimental results show that the gain of the feed is about 10 dBi, and the VSWR is less than 2:1. In addition, the feed has a low axial ratio, fixed phase centre location, and constant beam width in the range of 0.4 to 2 GHz.
AB - In traditional antenna design, metal components are not placed in the central part of the antenna as they change the characteristics of near field radiation. However, we show that placing a metal ring in the centre of the strip lines, which connect the ends of folded high-frequency dipoles, does not damage the performance of the feed. Instead it significantly improves the voltage standing wave ratio of the feed whilst other performance indicators are not compromised. Thus, our findings show an excellent way of improving the wide band feed. Based on this foundation, a new circularly polarised feed for operation between 0.4 to 2 GHz is introduced for the Chinese Spectral Radioheliograph in this paper. The issue of a feed impedance matching network is investigated. By optimising the impedance matching, the performance of the feed is enhanced with respect to the previous realisations of the Eleven feed. The simulation and experimental results show that the gain of the feed is about 10 dBi, and the VSWR is less than 2:1. In addition, the feed has a low axial ratio, fixed phase centre location, and constant beam width in the range of 0.4 to 2 GHz.
KW - Astronomical instrumentation
KW - Methods and techniques
KW - Methods: analytical
U2 - 10.1017/pasa.2016.51
DO - 10.1017/pasa.2016.51
M3 - Article
AN - SCOPUS:85003955313
VL - 33
JO - Publications of the Astronomical Society of Australia
JF - Publications of the Astronomical Society of Australia
SN - 1323-3580
M1 - e061
ER -