KEY TERMS

SPECTRAL SIGNATURE
- combination of emitted, reflected or absorbed electromagnetic radiation that is used to identify an object

RADAR-CROSS SECTION
- refers to the degree of the radar detectability of an object
2-WAY EVASION
Stealth works in both ways, not just as a shield to hide yourself. The Ohio State University engineers have invented a radar system that is virtually undetectable, because its signal resembles random noise, which almost all radio systems are designed to eliminate. Hence, these radar waves will go undetected, and will not interfere with TV, radio, and other communication devices. The radar can then be tuned to penetrate solid walls allowing the military to spot enemy soldiers inside a building without the radar signal being detected. The radar can further be applied in fields like law enforcement, the military, and disaster rescue.

Physicists have also created 'stealth' antennas made of plasma and gas. These antennas "vanish" when cooled, a critical quality that will come in handy on the battlefields, where antennas need to be kept out of sight. Furthermore, these new ‘stealth antennas are impervious to signal jammings from the enemy.
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​STEALTH AIR-TO-SURFACE BOMBERS
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RADAR-ABSORBENT MATERIALS (RAM)
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​These are stealth-related materials that breaks or blend object into the background, that allow the object to evade radar detection. These materials can help to compress the radar cross-section of the object. RAM does not imply that the object is invisible.

4 MAIN TYPES OF RAM

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The bombers however, still has the noisiest component of all aeroplanes - the engine system. Stealth bombers typically have their engine systems that are deeply embedded inside the aeroplane with thick layer of hull materials, which significantly reduce the reverberation of noise from the aeroplane, hence muffling the noise produced. This technique of embedding the engine system also allow the hull to be designed in such a way to regulate the heat signature of the aeroplane, and to dissipate heat in a regulated manner, to minimise the infrared signature exposed to the environment. Exhaust of stealth aeroplanes also pass through specialised cooling vents before being expelled from the aeroplanes.
RADAR EVASION
Jaumann absorber
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A device that uses wave interference to neutralise the reflected wave.
Foam absorber
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Like anechoic chambers (think soundproof rooms), lined in the hull of the aeroplane to reduce electromagnetic radiation reflection.
Iron ball paint
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Tiny particles of the paint allows for the absorption of the radar waves, and converting the captured waves into heat, which is then dissipated through the aeroplane.
Salisbury screen
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One of the earliest forms of RAM, which basically functioned like anti-reflective optical coating used on lenses to reduce reflection of light, and the screen neutralises the visible light waves.
Present.
One awe-inspiring application of stealth-related technologies is the stealth bombers. This stealth military asset is much unlike the traditional bombers - in place of tiered design of a fuselage, a pair of wings, and 3 stabilisers attached to the tail of the plane, stealth bombers are radically different: It has only one wing. Think of a boomerang. This is the flying wing design, which is designed from the outset to bear the ​dimmest spectral signature, and to be more efficient than a traditional aeroplane. The lack of a fuselage and stabilisers eliminates air drag significant - which means greater fuel efficiency.
These bombers possess a low radar-cross section, which essentially means the objective of the aeroplane is low-observability. Stealth bombers are invisible in a couple of ways, but just not invisible to the human eye within discernible distance. What it does possess, is a streamlined body profile, that allows the aeroplane to nearly blend into the background when observed from a significant distance, e.g., when observed from ground level. The bombers are also surfaced with chemically-treated materials that absorbs enemy electromagnetic radiations, which essentially inundate the infrared-driven object detection systems of the enemies.
