Radarquerschnitts

Radarquerschnitt, commonly abbreviated as RCS, is a quantitative measure of an object's detectability by radar. It represents the area that would intercept a given amount of incident radar energy and adequately reflect it back toward the radar source. The effective cross‑section is expressed in square meters and is derived from the power returned to the radar receiver relative to the incident power.

The concept of radar cross‑section emerged during the development of active radar systems in the 1930s and 1940s, primarily to evaluate aircraft stealth capabilities. Originally, RCS was measured by placing a target in a radar range chamber and recording the backscattered signal. Over time, more sophisticated techniques such as the use of anechoic chambers, near‑field to far‑field transformations, and computational electromagnetic simulations have been developed. ANSI/AGMA standards and ISO 17093 provide guidelines for RCS measurement and reporting.

RCS is influenced by an object’s size, shape, material, surface roughness, and orientation relative to the radar wavevector. For metallic structures, smooth surfaces tend to produce specular reflections, leading to higher RCS, whereas corrugated or radar‑absorbent coatings can significantly reduce it. Stealth aircraft employ advanced shaping, radar‑absorbent materials, and low‑observable design to achieve RCS levels as low as 0.001 square meters or less at common radar frequencies.

Applications of RCS measurement extend beyond military stealth. Naval vessels, ground vehicles, and even weather phenomena such as raindrops and hailstones have calculated RCS values to aid in radar system design and signal interpretation. Advances in metamaterials and active cloaking concepts continue to push the boundaries of how minimal a radar signature can become, thereby influencing both defense strategy and civilian radar system development.