Design of Low-RCS Vivaldi Antenna Based on Characteristic Mode Analysis

In this letter, a low radar cross section (RCS) Vivaldi antenna is designed based on characteristic mode analysis (CMA). The characteristic mode theory (CMT) is first applied to wideband RCS reduction of the Vivaldi antenna. Three typical frequency points are selected at low (8 GHz), medium (10 GHz) and high frequency (12 GHz), respectively, for CMA with the aim of realizing broadband RCS reduction. Different from the traditional analysis of mode weighting coefficient (MWC) and current distribution, the analysis of the magnitude and phase of each mode is further introduced, which makes the analysis more effective for guiding the RCS reduction design. By modification, the cheapest and most effective way, scattering currents corresponding to the dominant scattering modes are effectively suppressed so that the monostatic RCS is reduced as much as possible. Simulated and measured results show that compared with the reference antenna, the peak reduction of RCS of the proposed antenna reaches 27.36 dB, and the design doesn't degrade the radiation performance.