Radar Cross Section

The B-2 stealth bomber in Figure 1-38 is made by Northrop Grumman. Virtually all external parts are made of various composite materials because of their radar-absorption characteristics and/or their capability to be formed to shapes that naturally lower the radar cross section of the plane. However, the details are not publicly available, nor are they for the Lockheed Martin F-117A stealth fighter. 

I. P. Theron, E. K. Walton, and S. Gunawan, Compact range radar cross-section measurements using a noise radar , IEEE Trans. Antennas Propagat., vol. 46, pp. 1285-1288, Sept. 1998. 

D. Mensa. High Resolution Radar Cross-Section Imaging, Artech House, 1991. 

The most common mode of aircraft detection is radar. Essentially, radar is the detection of radio waves that have been thrown out and which bounce off objects returning to the site of origin. Today s radar, if properly used, can help identify the location, speed, and identity of the aircraft. The radar cross-section (RCS) of an aircraft is how much echo the plane sends from radar. Birds have an RCS of about 0.01 m. The Stealth Bomber has an RCS of 0.75 m. The Stealth Bomber and many stealth aircraft gain their stealth character from both the shape of the aircraft and the presence of radar absorbing material (RAM), which is made to absorb and eliminate radio waves rather than reflect them. Most of the RAM materials are polymeric. 

In addition to specific impulse, the vehicle requirements usually influence propellant selection in terms of storability, density, toxicity, and other hazards, and other application-sensitive factors, including exhaust plume properties and radar cross section and radiation emissions. Other factors being essentially equal, the higher the heat of reaction of a propellant (or combination). Hie more attractive die propellant. Sharp exceptions to this rule occur in some missiles because of volume limitations, the need for smokeless exhaust or similar restraints. 

Microwave-absorbing materials are currently in high demand for many expanded EMI shielding and radar cross section reduction applications with both commercial and defense purposes. The nanostructured materials have attraction for microwave radiation absorbing and shielding materials in the high-frequency range due... 

A radar backscatter model that yields normalised radar cross section (NRCS), given a local ocean surface wave spectrum. 

From these calculated wave spectra, the normalised radar cross sections (o °) were calculated using the VIERS-1 radar backscatter module (Janssen et al. 1998). This is a more or less standard composite model which includes the two-scale effect (Bragg backscatter influenced by longer wave... 

Based on the classical Radar Equation, a normalising relationship between the pixel intensity, X, in the images and the Normalised Radar Cross Section (NRCS), a0, of the sea surface was established as ... 

The standard SAR image processing which allows to delineate the processes on sea the surface includes, in particular, image section and NRCS contrast estimation. The wave damping ratio (the ratio of the spectral densities of Bragg waves (S) with wave number k or the normalised radar cross section (NRCS) (cr0) of spill-free and spill-covered sea surface) or contrast ... 

Radar is the acronym for radio detection and ranging1. This means that electromagnetic waves are used to measure the distance between a radar antenna and an obstacle. The simple form of the radar equation expresses the maximum radar range Rmax in terms of the key radar parameters and the radar cross section of the target. 

Many of the materials, processes and manufacturing methods discussed earlier in the chapter have been implemented in their construction. Another interesting relatively new field of development in the military aircraft sphere is that of stealth , a concept that requires the designer to achieve the smallest possible radar cross-section to reduce the chances of early detection by defending radar sets. The essential compound curvature of the airframe with constant change of radius is much easier to form in... 

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Density Superior drape to to reduce radar cross section... 

The definition of the radar cross section (RCS) is illustrated in Fig. 2.5. Here a fictitious flat plate, with area a ant, intercepts an incident plane wave with power density —that is, the intercepted power is dant b,. 

The radar cross section of the antenna mode component is now defined as an area da t so large that the power density <4>ant associated with the fictitious plate is the same as the power density associated with the antenna mode component that is, we set... 

Substituting (2.5) and (2.7) into (2.6) yields the radar cross section of the antenna mode ... 

Expression (2.8) will in general not constitute the entire RCS of an antenna. In fact, it is only a component of the total radar cross section, which implies that there may be something else. This is usually called the residual (or structural) component a res- It was defined earlier as whatever must be added to the field associated with a am as given by (2.8) in order to obtain the field associated with the total antenna RCS, that is. 

The observation that loading an array with load impedances Zi = Z produces a backscattered radar cross section 6 dB below the backscatter obtained for the... 

This definition has been known at least since World War II [55] and has been widely quoted eversince [37, 38, 56-58]. What is more, it has often been implied that this class of antenna represents the ultimate as far as low radar cross section is concerned and, consequently, should be treated with great respect ... 

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