Analysis of RCS of Low Observable Aircraft in VHF Band

Abstract

Electromagnetic signatures of a low observable aircraft have been studied in VHF band. First of all, a three-dimensional model of the aircraft has been established for numerical computation. Then, monostatic and bistatic radar cross sections (RCS) have been calculated. The model of the aircraft is made by a curved surface, and commercial as well as in-house three-dimensional electromagnetic code which is based on the method of moments (MoM) is utilized to calculate the RCS. A characteristic basis function method (CBFM) and a multilevel fast multipole algorithm (MLFMA) have been applied to analyze electrically large objects. The change of the monostatic RCS is very large depending on the direction of the incident wave. The maximum value is about 42 dBsm at the top and bottom of the aircraft, and the minimum value is about −10 dBsm at the front and back of the aircraft. It is found that the bistatic RCS also changes dramatically depending on the direction of the incident wave. The direction of maximum RCS occurs around specular reflection, and the value of maximum RCS ranges from 27 dBsm to 43 dBsm. On the other hand, the direction of the minimum RCS occurs irregularly, and the value is in the level of −30 dBsm.

Statistical modeling for the monostatic radar cross‐section characteristics of stealth aircraft using the Swerling‐chi/inverse generalized gamma composite distribution model

“…RCS results are calculated using the ACA method provided in Altair FEKO 2020. As comparisons, Figure 2B illustrates the corresponding RCS simulation results of F‐22 aircraft using the Multilevel Fast Multipole Method (MLFMM) method, which is plotted with the red line in Figure 2B provided in Reference 1. It can be found that these two RCS simulation results are very close.…”

“…Comparisons of monostatic RCS of the F‐22 aircraft model in the xy plane with VV polarization at the frequency of 230 MHz (A) Simulated RCS results using the ACA method (B) Simulated RCS results in Reference 1 using the MLFMM method…”

“…Radar cross-section (RCS) is an important parameter of the electromagnetic scattering characteristics of stealth aircrafts. [1][2][3][4] As the stealth target RCS fluctuates rapidly with the variation of aspect angle, it is usually described using statistical distributions. [5][6][7][8][9] For example, χ 2 distribution, lognormal distribution, and Weibull distribution have been used for modeling RCS statistical characteristics of stealth aircrafts.…”

“…Radar cross‐section (RCS) is an important parameter of the electromagnetic scattering characteristics of stealth aircrafts 1–4 . As the stealth target RCS fluctuates rapidly with the variation of aspect angle, it is usually described using statistical distributions 5–9 .…”

Research on electromagnetic scattering characteristics of dipole clusters

“…However, for very dense chaff clouds that have just dispersed, the coupling and shielding effects between dipoles need to be considered. If full-wave numerical methods such as method of moment (MoM) are used to calculate the scattering of electrically large objects such as aircraft and ships, 8,9 the mutual coupling between subscatters will be strictly considered. This results in a large number of matrix equations, which require a large amount of storage and a long running time.…”