A Novel Design of Low RCS Vivaldi Antenna for Electronic Warfare Application

Vivaldi antenna is an ultrawideband high gain antenna extensively used in Electronic Warfare (EW) radar system. When such metallic antenna is mounted on a stealth platform, it is required to have low radar cross section (RCS) besides having a good radiation performance. In this paper, a novel design of Vivaldi antenna is presented which shows reduced structural RCS over the entire operating frequency range (2–18 GHz) along with high gain (>6 dBi) and low VSWR (<2.5). The RCS reduction is achieved by modifying the antenna structure. The metal part of the antenna is removed and additional slots are introduced without disturbing the radiating taper portion. The monostatic/bistatic RCS of Vivaldi antenna for broadside plane wave incidence is presented for different azimuth and elevation cuts. It is shown that the radiation performance of the Vivaldi antenna is well maintained in terms of VSWR and gain with an RCS reduction of 4 dB (average). Such a low-observable end-fire antenna is a preferred choice for stealth platforms.