Which statement describes a limitation of phased array antennas?

Which statement describes a limitation of phased array antennas?

• A. They have extremely low data rates
• B. They are complex, expensive, heavier, with higher losses in feed distribution
• C. They require no maintenance
• D. They operate only at DC

Answer: (B)

Phased array antennas have the ability to steer beams electronically by adjusting the phase across many elements, which is their big advantage. But making that capability work well introduces practical drawbacks. Coordinating many individual RF paths—each element needing its own phase shifter, amplifier, splitter, and interconnecting feed network—adds substantial complexity. That complexity translates directly into higher manufacturing cost and more weight, since you’re carrying more hardware and longer, more intricate signal routes. The feed network also incurs losses. Every splitter, phase shifter, and connector adds some loss, and those losses accumulate when you have dozens or hundreds of elements. That reduces overall efficiency and can require more powerful amplifiers or extra cooling, which in turn adds to weight and cost. All of this also means tighter tolerances and more frequent calibration, so maintenance becomes more involved than for a simpler, single-element antenna. In contrast, statements about very low data rates or operation at DC don’t reflect how phased arrays function. They operate with RF signals and can support high data rates depending on the system design, and they do require maintenance and calibration rather than being maintenance-free.

Phased array antennas have the ability to steer beams electronically by adjusting the phase across many elements, which is their big advantage. But making that capability work well introduces practical drawbacks. Coordinating many individual RF paths—each element needing its own phase shifter, amplifier, splitter, and interconnecting feed network—adds substantial complexity. That complexity translates directly into higher manufacturing cost and more weight, since you’re carrying more hardware and longer, more intricate signal routes.

The feed network also incurs losses. Every splitter, phase shifter, and connector adds some loss, and those losses accumulate when you have dozens or hundreds of elements. That reduces overall efficiency and can require more powerful amplifiers or extra cooling, which in turn adds to weight and cost. All of this also means tighter tolerances and more frequent calibration, so maintenance becomes more involved than for a simpler, single-element antenna.

In contrast, statements about very low data rates or operation at DC don’t reflect how phased arrays function. They operate with RF signals and can support high data rates depending on the system design, and they do require maintenance and calibration rather than being maintenance-free.