Which statement correctly describes array nulling?

• A. Nulling suppresses interference in a direction
• B. Nulling redirects the main lobe toward a target
• C. Nulling increases the array's physical size
• D. Nulling improves sidelobe suppression equally to beam steering

Answer: (A)

Array nulling focuses on shaping the antenna pattern to place a deep null in the direction of an undesired signal. By adjusting the relative amplitudes and phases of each array element, the combined field cancels signals coming from that specific direction, reducing interference without moving the main sensing direction.

This is different from beam steering, which aims the main lobe toward a target; nulling keeps the main lobe where you want for sensing and selectively reduces energy from the interferer. It’s an electronic pattern adjustment, not a physical change to the array’s size. Also, nulling targets interference in a particular direction and doesn’t automatically enhance sidelobe suppression everywhere to the same extent; achieving a null can come at the cost of some gain in other directions, depending on the constraints used.