The beam steering of an annular phased array transducer is ______.

• A. Electrical
• B. Mechanical
• C. Hydraulic
• D. Pneumatic

Answer: (B)

The behavior of the beam in an annular array is governed by its circular, concentric-ring geometry. Because the rings are symmetric around the axis, steering the beam off-axis is most practically achieved by moving the transducer itself (mechanical scanning) rather than by applying complex phase delays across the rings. In practice, electronic steering via phasing is common for linear or convex arrays, but for an annular array the usual method to sweep the beam across the field is to use mechanical motion of the transducer. Hydraulic or pneumatic actuation isn’t how the beam is steered in this context, so the correct choice is mechanical.