Radars use microwaves for several reasons:
Penetration: Microwaves have the ability to penetrate through various atmospheric conditions, such as rain, fog, and clouds, more effectively than higher-frequency waves like visible light or shorter radio waves. This makes them suitable for long-range detection and tracking, even in adverse weather conditions.
Size and Antenna Efficiency: Microwaves have wavelengths on the order of centimeters to millimeters, which allows for the construction of compact radar systems and antennas. The smaller size of microwave antennas enables the design of radar systems that can be installed on aircraft, ships, vehicles, and even handheld devices.
Reflectivity and Scattering: Microwaves interact differently with objects compared to visible light or other frequencies. They can reflect, scatter, or diffract when encountering objects in their path. This behavior allows radar systems to detect and analyze the reflections and scattering patterns to identify objects, determine their distance, velocity, size, and shape.
Low Atmospheric Absorption: Microwaves experience relatively low absorption by the Earth's atmosphere compared to higher-frequency waves. This property enables the radar signals to travel longer distances without significant attenuation, making them suitable for long-range surveillance and detection.
Frequency Allocation: The microwave frequency range, particularly the X-band (8-12 GHz) and S-band (2-4 GHz), has been designated for radar use by international agreements and regulatory bodies. This allocation ensures that radar systems operating in these frequency bands do not interfere with other communication systems and allows for effective coordination and integration of radar technology across various applications and industries.
Overall, the characteristics of microwaves, including their ability to penetrate through various conditions, compact size, interaction with objects, low atmospheric absorption, and frequency allocation, make them well-suited for radar applications in fields such as aviation, maritime operations, weather monitoring, defense, and traffic control, among others.