Different types of radar scattering refer to various mechanisms by which radar waves interact with objects or surfaces, influencing how those objects appear in radar returns. The main types of radar broadcast include:
- Specular Array: Specular scattering occurs when radar waves are reflected off a smooth or flat surface in a single direction, similar to the reflection of light off a mirror. This type of scattering preserves the incident angle and can produce strong and distinct radar yields when the radar and target orientations are favorable.
- Diffuse Scattering: Diffuse scattering occurs when radar waves interact with rough or irregular surfaces, causing them to scatter in multiple directions. Unlike specular scattering, diffuse scattering does not maintain a distinct reflection angle and results in more dispersed radar performance. This type of scattering is common with natural surfaces like terrain, vegetation, and ocean waves.
- Multipath Scatter: Multipath scatter occurs when radar waves reflect off multiple surfaces or objects before reaching the radar receiver. This phenomenon can lead to complex interference patterns in radar outputs, particularly in environments with significant clutter or when radar waves bounce off structures or terrain features multiple times.
- Volume scattering: Volume scattering involves radar waves interacting with particles or elements distributed in a volume of space, such as atmospheric particles (like raindrops or snowflakes), clouds of dust or turbulent air masses. This type of scattering contributes to radar yields of precipitation, clouds, and other atmospheric phenomena.
Surface scattering refers specifically to the interactions of radar waves with the Earth’s surface or other large, relatively flat surfaces. Different types of surface scattering include:
- Bragg scattering: Bragg scattering occurs when radar waves interact with periodic or semi-periodic structures on the surface, such as waves on water or periodic roughness patterns on the ground. This type of scattering is wavelength dependent and can result in pronounced radar efficiencies when the wavelength matches the spacing of surface features.
- Rough surface diffusion: Rough surface diffusion encompasses both the specular and diffuse diffusion mechanisms mentioned previously. It occurs when radar waves encounter surfaces with irregularities or rough textures, causing them to scatter in various directions based on surface roughness characteristics. This type of diffusion is common in natural terrains such as forests, mountains and agricultural fields.
- Dielectric Scattering: Dielectric scattering involves radar waves interacting with surfaces based on their electrical properties and material composition. It considers how radar waves penetrate or interact with different materials (such as soil, vegetation, or man-made structures) and reflect or scatter based on their dielectric constants and surface roughness.
Understanding these different types of scattering is essential in radar system design, signal processing, and interpretation of radar yields for applications such as remote sensing, weather monitoring, and military surveillance. Each type of scattering influences how radar waves interact with objects and environments, affecting the quality and interpretation of radar data.