05-07-2012, 10:37 AM
Vector Network Analyzer and its application for measurement of Radar Cross Section (RCS)
[attachment=26768]
INTRODUCTION
Stealth technology is a sub-discipline of military tactics and passive electronic countermeasures which cover a range of techniques used with personnel, aircraft, ships, submarines, and missiles, to make them less visible (ideally invisible) to radar, infrared sonar and other detection methods. Stealth technology (or LO for "low observability") is not a single technology. It is a combination of technologies that attempt to greatly reduce the distances at which a person or vehicle can be detected; in particular radar cross section reductions.
Electromagnetic wave
Electromagnetic waves are formed by the vibrations of electric and magnetic fields. These fields are perpendicular to one another in the direction of the wave is traveling. Once formed, this energy travels at the speed of light until further interaction with matter. James Clerk Maxwell first formally postulated electromagnetic waves. Maxwell derived a wave form of the electric and magnetic equations, thus uncovering the wave-like nature of electric and magnetic fields, and their symmetry. Because the speed of EM waves predicted by the wave equation coincided with the measured speed of light, Maxwell concluded that light itself is an EM wave.
Network Analyzer
Network analyzers are powerful instruments that, when properly used, provide unparalleled accuracy. Indispensable throughout an enormous range of applications and industries, network analyzers are particularly useful in measuring linear characteristics of radio frequency (RF) components and device also use modern network analyzers in more specific applications, such as signal integrity and materials measurement
Principle
Network is a frequently used term that has many modern-day definitions. With respect to network analysis, a network is a group of interconnected electrical components. One function that a network analyzer performs is to quantify the impedance mismatch between two RF components to maximize power efficiency and signal integrity. Each time an RF signal leaves one component and enters another, portions of the signal are reflected and transmitted. Consider the analogy shown in Figure 2.2(a).
ANECHOIC CHAMBER
Definition
An anechoic chamber (an-echoic or non-echoing) is a room designed to stop reflections of either sound or electromagnetic waves. They are also insulated from exterior sources of noise. The combination of both aspects means they simulate a quiet open-space of infinite dimension, which is useful when exterior influences would otherwise give false results. Anechoic chambers range from small compartments to ones as large as aircraft hangars. The size of the chamber depends on the size of the objects to be tested and the frequency range of the signals used, although scale models can sometimes be used by testing at shorter wavelengths. An anechoic chamber is a room, where the target is placed on a rotating pillar in the center, and the walls, floors and ceiling are covered by stacks of radar absorbing material. These absorbers prevent corruption of the measurement due to reflections. A compact range is an anechoic chamber with a reflector to simulate far field conditions.
CONCLUSION
We have studied Vector Network Analyzer and its application for measurement of Radar Cross Section (RCS). The RCS of different objects like sphere, metal plate and cylinder were measured. The results of this work would not only be beneficial to foster general understanding of radar target detection, but would also facilitate the provision of concise and comparable radar range calculations.
[attachment=26768]
INTRODUCTION
Stealth technology is a sub-discipline of military tactics and passive electronic countermeasures which cover a range of techniques used with personnel, aircraft, ships, submarines, and missiles, to make them less visible (ideally invisible) to radar, infrared sonar and other detection methods. Stealth technology (or LO for "low observability") is not a single technology. It is a combination of technologies that attempt to greatly reduce the distances at which a person or vehicle can be detected; in particular radar cross section reductions.
Electromagnetic wave
Electromagnetic waves are formed by the vibrations of electric and magnetic fields. These fields are perpendicular to one another in the direction of the wave is traveling. Once formed, this energy travels at the speed of light until further interaction with matter. James Clerk Maxwell first formally postulated electromagnetic waves. Maxwell derived a wave form of the electric and magnetic equations, thus uncovering the wave-like nature of electric and magnetic fields, and their symmetry. Because the speed of EM waves predicted by the wave equation coincided with the measured speed of light, Maxwell concluded that light itself is an EM wave.
Network Analyzer
Network analyzers are powerful instruments that, when properly used, provide unparalleled accuracy. Indispensable throughout an enormous range of applications and industries, network analyzers are particularly useful in measuring linear characteristics of radio frequency (RF) components and device also use modern network analyzers in more specific applications, such as signal integrity and materials measurement
Principle
Network is a frequently used term that has many modern-day definitions. With respect to network analysis, a network is a group of interconnected electrical components. One function that a network analyzer performs is to quantify the impedance mismatch between two RF components to maximize power efficiency and signal integrity. Each time an RF signal leaves one component and enters another, portions of the signal are reflected and transmitted. Consider the analogy shown in Figure 2.2(a).
ANECHOIC CHAMBER
Definition
An anechoic chamber (an-echoic or non-echoing) is a room designed to stop reflections of either sound or electromagnetic waves. They are also insulated from exterior sources of noise. The combination of both aspects means they simulate a quiet open-space of infinite dimension, which is useful when exterior influences would otherwise give false results. Anechoic chambers range from small compartments to ones as large as aircraft hangars. The size of the chamber depends on the size of the objects to be tested and the frequency range of the signals used, although scale models can sometimes be used by testing at shorter wavelengths. An anechoic chamber is a room, where the target is placed on a rotating pillar in the center, and the walls, floors and ceiling are covered by stacks of radar absorbing material. These absorbers prevent corruption of the measurement due to reflections. A compact range is an anechoic chamber with a reflector to simulate far field conditions.
CONCLUSION
We have studied Vector Network Analyzer and its application for measurement of Radar Cross Section (RCS). The RCS of different objects like sphere, metal plate and cylinder were measured. The results of this work would not only be beneficial to foster general understanding of radar target detection, but would also facilitate the provision of concise and comparable radar range calculations.