Design of a Vivaldi antenna with wideband reduced radar cross section

In this paper, a low radar cross section (RCS) Vivaldi antenna is proposed. The main objective of this work is to achieve a reasonable RCS reduction without affecting the radiation performance of the antenna. With carefully inspecting the surface current distributions at different frequencies and realizing the critical role of the structural mode in reducing RCS, a simple and efficient object shaping method is employed by introducing a number of circular slots in the surface of the radiator to achieve the RCS reduction. These circular slots along the inner circular profile of the Vivaldi antenna can minimize the scattering along the surface of the radiator, which hence leads to a reduction in the monostatic RCS. Comparing the measured results between the reference antenna and the proposed antenna, a significant 11 dB RCS reduction is obtained while maintaining good radiation performance. Simulated and measured results including S-parameters, gain, RCS of the reference antenna and the proposed antenna are presented.