How does phase-shifter-based electronic scanning enable rapid beam steering?

How does phase-shifter-based electronic scanning enable rapid beam steering?

• A. By moving the antenna mechanically to sweep the beam.
• B. By time-sharing the transmitter power across elements.
• C. By adjusting phase delays across array elements, the constructive interference steers the main beam without moving the antenna.
• D. By demodulating the received signal at multiple frequencies.

Answer: (C)

Phase-shifter-based electronic scanning steers the radar beam by controlling the phase of the signal at each element of a antenna array. By applying a specific set of phase delays across the elements, the radiated waves interfere constructively in a chosen direction and destructively elsewhere, creating a main beam that points where you want. This phase progression effectively “tilts” the array's radiation pattern without moving any hardware. Because there are no mechanical parts to move, changing the beam direction is just updating the phase settings, which can be done in microseconds or faster. This enables truly rapid beam steering and the ability to switch directions quickly or even form multiple beams. Moving the antenna would be mechanical steering, which is slower and subject to wear and inertia. Time-sharing transmitter power across elements isn’t about steering the beam, and demodulating the received signal at multiple frequencies deals with signal processing, not directing where the beam is pointed.

Phase-shifter-based electronic scanning steers the radar beam by controlling the phase of the signal at each element of a antenna array. By applying a specific set of phase delays across the elements, the radiated waves interfere constructively in a chosen direction and destructively elsewhere, creating a main beam that points where you want. This phase progression effectively “tilts” the array's radiation pattern without moving any hardware.

Because there are no mechanical parts to move, changing the beam direction is just updating the phase settings, which can be done in microseconds or faster. This enables truly rapid beam steering and the ability to switch directions quickly or even form multiple beams.

Moving the antenna would be mechanical steering, which is slower and subject to wear and inertia. Time-sharing transmitter power across elements isn’t about steering the beam, and demodulating the received signal at multiple frequencies deals with signal processing, not directing where the beam is pointed.