Radar Cross Section Reduction of Wideband Vivaldi Antenna Arrays With Array-Level Scattering Cancellation

Wideband phased antenna arrays always contribute large radar cross section (RCS) to low-observed platforms. Low-scattering wideband phased antenna arrays are thus highly demanded. This article proposes to reduce the RCS of wideband phased antenna arrays through array-level scattering cancellation. Two types of Vivaldi antenna elements that exhibit almost the same scanning performance and operating bandwidth are developed. However, the tapered curves are intentionally designed to be different to achieve a 180° reflection phase difference. With these two types of Vivaldi antenna elements, a low-scattering Vivaldi antenna array ( $16\times16$ ) is developed by array-level scattering cancellation. A reference Vivaldi antenna array with a single type of antenna element is also developed. Simulation and measurement results of the reference and the proposed antenna array are compared to illustrate the effectiveness of the proposed RCS reduction technique. Both antenna arrays operate over the 8–12 GHz frequency band and scan up to ±60° in the E-/H-planes. However, the proposed Vivaldi antenna array achieves an average of 10 dB monostatic RCS reduction over 6–18 GHz. It indicates that the array-level scattering cancellation technique is promising for developing low-scattering wideband phased antenna arrays.