Analysis and Design of Conformal Antenna Cavity for RCS Reduction

The scattering characteristics of radar antenna cavity located at the nose of aircrafts have been widely studied. While there are still a lot of shallow cavities on the back or belly of the fuselage for the placement of conformal antennas, these cavities usually need to deal with the grazing incidence of radar waves. RCS reduction under such circumstances are still rarely studied. This paper will give feasible schemes to reduce the monostatic RCS within the scope of major threats of these cavities and verify them through simulation.

I. Introduction

Without considering the performance of radar stealth, the previous airborne antennas mostly adopt the design of protruding fuselage. In order to reduce the overall RCS, it is necessary to flatten the fuselage, which requires the aircraft designer to suppress the profile of the aircraft and avoid the uneven transition of the aircraft surface. Therefore, the concave shallow cavities shielded by radome are preferred to place the antennas inside. This paper will try to improve the stealth nerformance of these cavities mainly by three measures: 1)

Modify the shape of the cavity.

2)

Adjust the relative permittivity of the radome.

3)

Use radar absorbent material (RAM).