China
Africa
Explore chapters and articles related to this topic
Imaging
Published in C. R. Kitchin, Astrophysical Techniques, 2020
Active radar systems may use the same antenna both for transmission and reception (a mono-static radar) or two separate antennae (bi-static radar – usually with a significant spatial separation between the two antennae). Passive radar is a form of bi-static radar using some adventitious source as the radio signal transmitter. Mostly, to date, the sources have been terrestrial radio or TV broadcasting stations and they have been used to observe meteor trails. However, there seems to be no prohibitive reason why strong single astronomical radio point (or nearly so) sources (e.g., Cas A – ~3 kJy at 1 GHz or the Crab nebula – ~1 kJy at 1 GHz) should not be used similarly for observing other astronomical objects.
A ultra wideband dual-polarized antenna with high isolation degree for passive radar application
Published in Electromagnetics, 2021
Miao Wang, Xiuwen Tian, Lizhong Song
The UWB dual-polarized antenna is the key component of passive radar systems such as polarization sensitive missile guidance radar and electronic reconnaissance. It is an important task to design a low-cost, high-performance, stable and reliable UWB dual-polarized antenna for passive radar development. In order to improve the polarization isolation of dual polarization antenna, a technical scheme of composite UWB dual-polarized antenna is proposed in this paper The whole antenna is composed of a modified Vivaldi antenna and a folded dipole log periodic antenna, which makes full use of the structural characteristics of the two radiators and realizes the contactless assembling of the two polarization channels. Combined with the structural design of the antenna, the polarization isolation degree of the dual polarization antenna is significantly improved, which can form a better polarization channel and lay a good foundation for subsequent polarization signal processing. Based on the above ideas, a dual polarization antenna working within the frequency range of 3 GHz~8 GHz is designed. The simulation and experimental results verify the effectiveness of the design scheme. The research results can provide technical basis for engineering application.