Wideband Array Antenna And RCS Reduction

With the development of modern radar communication technologies, the radio system has higher requirements on the performance of antennas. Generally speaking, the antenna need to be small enough and have a wide working frequency band simultaneously. The cost of a phased array radar system is quite high. So it is usually required to be able to work in wide or ultra-wide band to save cost. This is the one hand, on the other hand is that the antenna array can get more information through the wide-band performance, which is widely used in targets imaging and electronic countermeasure when the air vehicle is on a mission.In addition, it has been apparent for some time that the development of increasingly sophisticated detection systems threatens to reduce the mission effectiveness of many types of weapons platforms. Strong attention is now being given to methods of increasing survivability by reducing detectability. Because of the specific configuration, most platforms can keep low detectability. But antennas can be the dominant scatterers while other electronic devices are buried under the platform. So reducing the RCS(Radar Cross Section) of the platform by controlling the antenna’s scattering performance has a vital practical significance.This thesis specifically focuses on the scattering characteristics of Vivaldi antennas, certainly the radiating characteristics are also considered to guarantee that the antenna can work. The specific research contents include:(1) First of all, we design 4 types of Vivaldi antenas, and this section concentrates on the connection between the scattering characteristics and the impedance characteristics.(2) We design and process a bilateral Vivaldi antenna array which covers the frequency ranges from 4GHz to 14 GHz.(3) We analyse the RCS of the bilateral Vivaldi antenna array due to its reradiation, a remarkable RCS reduction in low frequency band is given by optimizing the structure of the array’s edge. After this, we discuss the scattering characteristics while the antenna array is mounted on a metal ground. By changing the shape of the ground, an effective RCS reduction is obtained. Moreover, in these two cases, the bilateral Vivaldi antenna array can maintain acceptable radiating performance.