Radar Cross Section (RCS)

Radar Cross Section

Thank you for your attention!

And one more thing...

• Defination:

Introduction

Dependence

• Properties of scattering objects

• Denoted by and measured in m2

• Electromagnetic Defination

RCS of the target depends upon

Measure of the targets ability to reflect radar signal in the direction of the radar reciever

• Material of the target

• Relative size of the target (wavelength)

• Incident angle

• Reflected angle

Regions

Reyliegh region

• object dimension <<

• RCS is directly proportional to (Frequency)

• RCS depends more on volume then on shape of objects

• eg. Rain

Resonance Region

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• Object dimension approximately equal to

Conclusion

Optical Reigion

• Object dimension >>

• RCS depends more on shape then projected area

• eg. Aircrafts, etc.

• RCS: measure of the target ability to reflect the radar signal
• dependance of RCS
• three important region:

• Reyliegh region
• Resonance region
• Optical region

Reduction Of RCS

• Redirecting electromagnetic waves from radars
• Using radar-absorbent material
• Active cancellation
• Camouflage by blending into the background visual clutter

• The use of stealth technology to reduce radar cross section decreases the target detection of military aircrafts.
• Used techniques like

• The stealth technology depends of the used radar transmitters frequency

HMS Helsingborg used by the Royal Swedish Navy

B-2 Spirit is an American heavy bomber with low observable stealth technology

Forbin, a modern frigate of the French navy.

RCS Of Simple Targets

• RCS Of Sphere

• RCS Of Thin Wire

• RCS Of Flat Plate

• RCS Of Cone Sphere

• The sphere is unique in that the RCS is independent of both wavelength and aspect, and in that its RCS is the same as the physical cross section

RCS Of Sphere

• the RCS of a target depends upon its physical size

• the RCS of a sphere of radius r is,

• The RCS of all other reflecting elements is larger than the physical cross section over some range of aspect.

• A sphere with diameter 3.6 meters (12 feet) would be needed to provide 10 m2 RCS.

• Because of its small RCS compared to its physical size, the sphere is not a practical element for recreational boats.

RCS of Sphere

• function of length, dimeter, angle of incidence & frequency signal
• It is larger when viewed broadside
• as the viewing angle decreses from 90 the RCS decreses

RCS Of Thin Wire

• the response is narrower along the longer side of the plate than along the shorter side.
• The figure shows that the effective RCS of the flat plate falls off rapidly as the elevation angle increases and it also falls off though not as rapidly as the azimuth angle increases.
• The peak RCS increases, and the half-power response width decreases, as physical size increases

RCS of Flat Plate

• Thus, increasing the size of a flat plate increases the peak RCS but decreases the response width.

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RCS of Cone Sphere

• cone whos base is capped with sphere
• RCSof cone sphere with 30 cone angle as a function of

• the cross section from the rear side is longer then the front side because of the sphere part
• a large value of the cone olso occurs when radar views the cone perpendicular to the surface
• the approx. RCS from nose on direction is 0.1

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presentation by

Prasad Dhuri