Wenfeng Sun

Efficiency Analysis on the Electromagnetism Scattering Characteristics of the Bistatic Radar

An electromagnetism scattering characteristics of Stealth target is a base for bistatic radar design. To study anti-stealth technology of bistatic radar, the radar cross section (RCS) of F-22 are calculated and measured by a true contrail. The simulation conclusion is accordant with the theory. Some valuable data can be provided as the theoretical bases for the design of anti-stealth radar systems．

Research on the development of space target detecting system and three-dimensional reconstruction technology

With the development of space technology, the number of spacecrafts and debris are increasing year by year. The demand for detecting and identification of spacecraft is growing strongly, which provides support to the cataloguing, crash warning and protection of aerospace vehicles. The majority of existing approaches for three-dimensional reconstruction is scattering centres correlation, which is based on the radar high resolution range profile (HRRP). This paper proposes a novel method to reconstruct the threedimensional scattering centre structure of target from a sequence of radar ISAR images, which mainly consists of three steps. First is the azimuth scaling of consecutive ISAR images based on fractional Fourier transform (FrFT). The later is the extraction of scattering centres and matching between adjacent ISAR images using grid method. Finally, according to the coordinate matrix of scattering centres, the three-dimensional scattering centre structure is reconstructed using improved factorization method. The three-dimensional structure is featured with stable and intuitive characteristic, which provides a new way to improve the identification probability and reduce the complexity of the model matching library. A satellite model is reconstructed using the proposed method from four consecutive ISAR images. The simulation results prove that the method has gotten a satisfied consistency and accuracy.

Research on the bastatic RCS characteristics of stealth aircraft

An electromagnetism scattering characteristics of Stealth target is a base for bistatic radar design. To study anti- stealth technology of bistatic radar, the radar cross section(RCS) of F-22 are calculated and measured by a true contrail. The simulation conclusion is accordant with the theory. Some valuable data can be provided as the theoretical bases for the design of anti-stealth radar systems.

Scattering characteristic analysis of dual-band for new precipitation radar

Aiming at the limitation of the TRMM Radar, we study on the next generation precipitation radar - GPM DPR radar, which not only works in the Ku-band, but also the Ka-band, for the global precipitation measurement. In this paper, the scattering characteristic of precipitation particles in the Ku-band and Ka-band has been analyzed in theory. Firstly, the model of precipitation is set up. Secondly, scattering and attenuation characteristics of rainfall group model from micro and macro point of view in Ku-band and Ka-band are analyzed. Attenuation properties of double-wave radar signal are quantitative calculated. Finally, simulation results demonstrate that the method using Ku-band and Ka-band measuring precipitation particles can extend detection range, differentiate type of the rainfall and develop measure precision. It is shown that scattering characteristic analysis of dual-band for new precipitation radar will leads to great significance for development of precipitation radar in the future. (4 pages)

RCS simulation of the satellite target based on multi-layer material

A modeling and calculation method for the RCS of complicated satellite targets is given in this paper, and the method is applied in the calculation of cube and cylinder with perfect conductor characteristic. Finally, the paper gives the instance of calculation to satellite targets RCS, and contrasts the result between satellite with metal and satellite with multi-layer material. We get the conclusion that the method adopted in the paper can simulate the message of dielectric surface and effectively and fleetly solve the problem of multi-layer material for complicated targets.

Cross-Range Super-Resolution Algorithm Based on Non-synthetic Aperture Radar

The cross-range resolution of a traditional radar depends on its antenna beam width and The distance between radar and target. The resolution of non-synthetic aperture radar is usually low due to the limited antenna aperture. This paper presents cross-range super-resolution algorithm based on principle components linear prediction in the sub bands, in order to improve the angle resolution of the short-distance scattered points in azimuth for low SNR. The experiments show that the proposed algorithm has greatly improved the cross-range resolution of non-synthetic aperture radar.

Design of a broadband microstrip 180° hybrid

The 180° hybrid is a fundamental component in microwave circuit. Its inherently a narrow-band structure. This paper presents the design and performance of a broadband microstrip 180° hybrid operating from 3 to 5 GHz. The hybrid is composed of a power divider and a marchand balun. By designing a new three coupled lines marchand balun structure instead of conventional narrowband balun, the hybrid achieves a broadband phase shifting and power splitting while maintaining perfect matching and output isolation. Simulated and measured results show that the designed 180° hybrid obtains good performances including low return loss level, low amplitude and phase difference between output ports and high isolation. Simple equations based on the scattering matrix are also presented in this paper.