Papers by Keyword: Radar Cross Section

Abstract: In order to improve the stealth performance of antenna, a metamaterial absorber with high absorption, polarization-insensitive and wide angle based on the electromagnetic resonance is designed. Using of ultra-thin characteristic of absorber, they are attached to the microstrip antenna to reduce its radar cross section. The simulation results show that the new microstrip antenna’s radiation performance remains unchanged compared with conventional microstrip antenna and it has obvious RCS reduction in its working band. While the maximum reduction can reach 28dB at working frequency, and the in-band reduction of antenna is above 3dB. This indicates that the absorber can be used for antennas’ in-band stealth.

Abstract: This paper presents a Radar Cross Section (RCS) reduction method for wind turbines. In the proposed method, a reshaping procedure is utilized to generate waves or bumps on the surface of the wind-turbine tower. As the tower is illuminated by electromagnetic waves, the reflected rays are perturbed by the convex structures and the RCS of the wind turbine is decreased. Test results conclude that our modeling method reduces the average RCS values. The scatterings in the directions of the convex structures are significantly declined.

Abstract: A broadband radar cross section (RCS) calculation approach is proposed based on the asymptotic waveform evaluation (AWE) technique. The equivalent dipole moment method (EDMM) is used to accelerate the process of filling the impedance matrix and more derivative matrices. So the broadband RCS is achieved quickly by using AWE technique and EDMM. Numerical results show that the computational efficiency is improved significantly by using the method presented in this paper with ensuring the accuracy.

Abstract: In this paper, a simulation method of detection probability of aircraft target for Over-The-Horizon Radar (OTHR) by computer is proposed. The effects of different ionosphere states on detection range for OTHR is concluded, which become constraint on simulation of detection probability. Taking variety of target RCS with attitude during flight through given track into consideration, simulation model of target dynamic RCS is established. Models of instantaneous detection probability and comprehensive detection probability are also presented. Then, detection probability of aircraft can be obtained through utilizing all models above based on given calculation steps. Simulations show that ionosphere state and target RCS have a great influence on detection probability.

Abstract: An ultra-wideband (UWB) circularly polarized complex spiral antenna with low radar cross section (RCS) is proposed in this paper. By replacing the metal reflect board of the antenna with a novel UWB frequency selective surface (FSS), the RCS of the spiral antenna is significantly reduced in a wide frequency range, while the radiation performances of the spiral antenna are maintained. The proposed antenna operates over the frequency band between 2GHz to 6.5GHz under the condition of axial ratio<3dB and |S₁₁| < - 10dB. Simulation and measurement results demonstrate the validation of broadband spiral antenna RCS reduction by using the novel UWB FSS.

Abstract: A high-order parabolic equation (PE) method is applied to calculate the Bistatic RCS of two-dimensional (2-D) Electrically-large Objects. According to the shapes of objexts, Crank-Nicolson and Pade (1,0) schemes are introduced to solve the high-order PE. The numerical results demonstrate that the method not only extends the accurate angle range but also decreases the rotation times and computational time in comparison with the traditional low-order parabolic equation method.

Abstract: CR-InSAR is developing continuously in recent years. It is an important technology in the field of monitoring crustal micro-deformation. Radar cross section of corner reflector is an important work foundation because only radar cross section of artificial corner reflector achieves maximum, it is easier to recognize it from SAR image and increase monitoring accuracy. Dihedral corner reflector is the simplest type in proving ground of Northwest of Beijing; its RCS research is a beneficial attempt helping to build up reasonable corner reflector layout. In the paper, establishing geometric model and subdivision model of dihedral corner reflector are based on FEKO software, and choosing physical optics to simulate RCS. The simulation result is good consistency with theoretical max value. Through analyzing RCS curve, it can help to provide guidance on how to set up corner reflector in the proving ground.

Abstract: To meet the demand for high precision measurements of radar cross section (RCS) in microwave anechoic chamber, the effect of angle repeatability of position servo system in background cancellation technology is analyzed and its error mathematical model is presented. Then a method of high speed synchronization angle measurement based on CPLD is proposed, which improves the precision of synchronization angle measurement in any fixed angle interval. The experiment results show that this method can effectively solve the accuracy of target RCS when rotating.

Abstract: The sky wave over-the-horizon radar (OTHR) works in high-frequency (HF) band, in which the stealth fighter RCS feature is largely different from that in microwave band. According to 3ds-Max model of F-22 fighter, RCS in HF band is computed by XFDTD software with different frequency, polarizations and angles. The simulation provides worthy preference on researching the ability of anti-stealth fighter of OTHR.

Abstract: As the classic analytical methods cannot calculate the electromagnetic scattering characteristics at Low Grazing Angle (LGA), a novel numerical method is presented by utilizing the Radar Cross Section (RCS) of the low grazing two-dimensional PM sea spectrum based on the triangles-based Physical Optics (PO) method in this paper. The calculated RCS is compared with the numerical calculation method of different targets and frequencies of incident wave. The results show that PO method is more accurate, especially under LGA condition, and it has a better agreement with the results calculated by commercial software FEKO.