How does antenna beamwidth affect resolution and scanning speed?

• A. Narrow beamwidth improves azimuth resolution but requires slower scanning; wide beamwidth increases coverage speed but reduces angular resolution
• B. Narrow beamwidth reduces resolution but increases scanning speed
• C. Beamwidth has no effect on resolution
• D. Wide beamwidth improves both resolution and speed

Answer: (A)

Beamwidth is the angular width of the radar’s main beam, and it sets both how finely you can distinguish targets in the azimuth direction and how much area you cover with each sweep. A narrow beam is like looking through a thin straw: you can separate targets that are very close in angle, so azimuth resolution is high. But because the beam only covers a small slice of the sky at any moment, you must scan more beam positions or dwell longer to cover the same sector, which slows the overall scanning rate. A wide beam, on the other hand, sweeps a larger angular area per scan, so you can cover ground faster, but that same wide beam blurs closely spaced targets, reducing angular (azimuth) resolution. This trade-off is exactly why a narrow beam improves resolution at the expense of speed, while a wide beam speeds up coverage but sacrifices resolution.