In-Band RCS Reduction Method for the Vivaldi Array Antennas Based on the Manipulation of the Antenna Mode Scattering Field

A novel in-band RCS reduction method based on the manipulation of the antenna mode scattering field (AMSF) is proposed for the Vivaldi antenna array. The mechanism of the impact of load impedance changes on the AMSF of the Vivaldi array is systematically analyzed for the first time, and a more accurate method for extracting array element AMSF with the changed load is proposed, which not only considers the influence of mutual coupling but also incorporates the AMSF with the 50-
$\Omega $
load. By adjusting the load impendence and optimizing the reflection phase distribution of the array with an optimization algorithm, the manipulated AMSF becomes the cancellation resource to achieve in-band RCS reduction. A
$1\times8$
Vivaldi linear array operating in 8–12 GHz is designed. Two scattering field cancellation cases are presented to verify the proposed method, which is proved to have the advantage of flexibly selecting the focus RCS reduction band. A prototype of the Vivaldi antenna array is fabricated and measured, further demonstrating the effectiveness of the in-band RCS reduction method proposed in this communication.