| 释义 |
fan beam fan beam[′fan ‚bēm] (electromagnetism) A radio beam having an elliptically shaped cross section in which the ratio of the major to the minor axis usually exceeds 3 to 1; the beam is broad in the vertical plane and narrow in the horizontal plane. A radar beam having the shape of a fan. fan beam Pencil-beam antenna pattern. Fan-beam antenna pattern.A fan-shaped radar beam, broad in the vertical plane and narrow in the horizontal plane. A fan beam allows only the measurement of the azimuth angle. Typically, a fan beam in aircraft surveillance radar is 1° to 2° in azimuth and 20° to 40°, or broader, in elevation. |