What is a primary limitation of parabolic antennas?

What is a primary limitation of parabolic antennas?

• A. Aperture blocking.
• B. They are omnidirectional.
• C. They have low gain.
• D. They are very expensive.

Answer: (A)

A parabolic antenna’s main limitation comes from aperture blockage. The feed horn and its support structure sit in front of the dish and block part of the aperture that would otherwise be used to collect or transmit energy. This obstruction reduces the effective aperture, causing diffraction that lowers overall efficiency and gain and can raise sidelobes. That blockage is the primary constraint on performance. As for the other statements: parabolic antennas are not omnidirectional—they provide high directional gain. They do not inherently have low gain. While large dishes can be expensive, cost isn’t a fundamental limitation of the antenna’s performance.

A parabolic antenna’s main limitation comes from aperture blockage. The feed horn and its support structure sit in front of the dish and block part of the aperture that would otherwise be used to collect or transmit energy. This obstruction reduces the effective aperture, causing diffraction that lowers overall efficiency and gain and can raise sidelobes. That blockage is the primary constraint on performance.

As for the other statements: parabolic antennas are not omnidirectional—they provide high directional gain. They do not inherently have low gain. While large dishes can be expensive, cost isn’t a fundamental limitation of the antenna’s performance.