Radar cross section is the measure of a target's ability to reflect radar signals in the direction of the radar receiver, . it is a measure of the ratio of backscatter power per steradian (unit solid angle) in the direction of the radar (from the target) to the power density that is intercepted by the target. | RADAR CROSS SECTION RCS Radar cross section is the measure of a target s ability to reflect radar signals in the direction of the radar receiver . it is a measure of the ratio of backscatter power per steradian unit solid angle in the direction of the radar from the target to the power density that is intercepted by the target. The RCS of a target can be viewed as a comparison of the strength of the reflected signal from a target to the reflected signal from a perfectly smooth sphere of cross sectional area of 1 m2 as shown in Figure 1 . The conceptual definition of RCS includes the fact that not all of the radiated energy falls on the target. A target s RCS o is most easily visualized as the product of three factors o Projected cross section x Reflectivity x Directivity . RCS o is used in Section 4-4 for an equation representing power reradiated from the target. Reflectivity The percent of intercepted power reradiated scattered by the target. Figure 1. Concept of Radar Cross Section Directivity The ratio of the power scattered back in the radar s direction to the power that would have been backscattered had the scattering been uniform in all directions . isotropically . Figures 2 and 3 show that RCS does not equal geometric area. For a sphere the RCS o Br2 where r is the radius of the sphere. The RCS of a sphere is independent of frequency if operating at sufficiently high frequencies where 8 Range and 8 radius r . Experimentally radar return reflected from a target is compared to the radar return reflected from a sphere which has a frontal or projected area of one square meter . diameter of about 44 in . Using the spherical shape aids in field or laboratory measurements since orientation or positioning of the sphere will not affect radar reflection intensity measurements as a flat plate would. If calibrated other sources cylinder flat plate or corner reflector etc. could be used for comparative measurements. Figure 2. RCS vs Physical Geometry To reduce .
