It is not possible (with today's technology) to make a plane completely invisible, but there are techniques to reduce the radar energy being reflected to the radar aerial. If reduced enough, the aircraft may appear smaller than it is, or even be classified by the system or operator as a non-aircraft. The aim is to reduce the Radar Cross Sectional Area (RCA) of the plane.
This technology is commonly referred to as 'stealth'. Modern stealth aircraft have an RCA much smaller than 1 square metre and in some circumstances can be as low as that of a large bird.
The most noticeable method of reducing RCA is to eliminate right angles and especially internal angles of 90 degrees. This is because energy entering will be reflected straight back the way it came. By using curves and obtuse or acute angles the energy is instead reflected away from the radar source. Use of clean lines and unbroken surfaces also reduces bumps and protrusions which also increase the RCA. By comparing a modern stealth fighter to older aircraft, it is clear that care has been taken to eliminate any feature which would reflect radar energy.
Another less obvious technique is to use radar absorbent paint. This expensive material works best against specific wavelengths of radar and will dramatically reduce the reflected energy. It works by allowing a proportion (about 50%) of the energy to be reflected and the remainder to penetrate. If the paint is exactly 1/4 of a wavelength think (hence the expense!) it will reflect off the inner paint surface and be 'antiphase' as it emerges again. This cancels out much of the radar energy in the same way that ripples in a pond from two pebbles cause patterns of high and low ripples.
Combinations of techniques such as these can reduce the aircraft RCA to that below the capability of most radars to detect at normal range. As the aircraft approached the radar emitter the radar signal will be increased until it is recognisable as an aircraft. However, by avoiding flying close to radars it may be possible to avoid detection at all, or at the least until it is too late to be a problem for the mission.
Ground penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. When the waves hit an object, the receiving antenna can be used to distinguish what it is. This can be used to find precious metals, like gold, underground.
It depends. Flying below radar is usually flying below the equipment used to detect things on radar. It could be a very high tower, hundreds of stories off of the ground, or it could be a satellite just a couple stories off of the ground.
Doppler RADAR measures the speed of objects using the Doppler effect (discovered by the Austrian mathematician and physicist Christian Andreas Doppler in 1842 at the Prague Polytechnic) in addition to the position measured by ordinary RADAR. The earliest version of Doppler RADAR was introduced by the U.S. Navy during WW2 on night fighters. Doppler RADARs are used now in aviation, sounding satellites, meteorology, police speed guns, radiology and healthcare (fall detection and risk assessment, nursing or clinic purpose), and bistatic radar (surface-to-air missile).
inclined plane wedge and the screw
It is an inclined plane.
The potion made the wizard invisible. The stealth plane is nearly invisible to radar.
The impedance of plane material is made equal to the impedance of air,in this way the waves sent by radar does not reflect by material of plane and pass through plane and do not come back to radar.That is why,plane remain invisible to radar.This material was invented by a PHD proffesor in UET Lahore Pakistan.
All stealth aircraft are built with the intent of being 'invisible' to radar. One of the best was the F-117.
Clouds are formed from water vapour - which is virtually invisible to radar.
Radar
radar
Stealth aircraft are not actually invisible to radar, but the waves reflected by it are far fewer than what is needed for identification as a plane. 1) The first way that it prevents this is by its shape, which reflects radar waves in random directions, rather than back to the receiver. 2) Secondly, the special paint used has the ability to absorb electromagnetic energy in the same frequency as radar impulses. 3) Finally, the mission profiles often allow stealth aircraft to fly close to the ground, where their radar return can be lost in ground clutter.
If you are referring to the missing Malaysian Airlines' plane, it is true that it had radar. However according to news reports, it has been suggested that the plane was deliberately flown too low which made radar detection impossible.
The F-117 Nighthawk cannot be detected by radar.
2. Mostly what we see as a result of Radar, is a little bright blob on a luminous screen! We may infer it is a plane, or a mountain or a ship, but only if we make a whole series of assumptions, and they are correct. 'Identification' is a long call.
RADAR
Shape and a special covering that renders invisible to radar