Which statement best describes a two-dimensional scanning planar array?

• A. Allows scanning in one dimension
• B. Allows scanning in two dimensions
• C. Is used only for fixed-point targets
• D. Requires no phase control

Answer: (B)

A planar, two-dimensional array is designed to steer its radar beam in two axes—azimuth and elevation—by applying phase shifts (or time delays) across the elements in both directions. Because the elements are laid out in a 2D grid, you can control the beam’s pointing anywhere in a vertical plane and horizontally as well, giving true scanning in two dimensions. This is what sets a planar array apart from a linear (one-dimensional) array, which can only steer the beam in a single plane. It’s not limited to fixed-point targets; the whole point of electronic scanning is to continuously point the beam toward moving or changing targets, and requiring phase control is essential to achieve that steering.