Which statement best describes antenna gain?

Which statement best describes antenna gain?

• A. Gain is independent of design
• B. Gain is the ratio of radiated power to input power (reflecting efficiency in transmit or receive)
• C. Gain is the same for any antenna
• D. Gain only applies to receiving antennas

Answer: (B)

Gain describes how an antenna concentrates energy in a particular direction compared to the power you put into the antenna. It is basically the ratio of the power that is radiated (in the direction you care about) to the input power, which reflects how efficiently the antenna converts input power into radiation in that direction (and, in receive mode, how effectively it captures energy from that direction). In other words, gain is the product of directivity (how narrowly the antenna can beam energy) and efficiency (how much of the input power is actually radiated or received). This depends on the antenna’s design, so gain isn’t the same for every antenna and isn’t independent of design. It also applies to both transmitting and receiving, not just one.

Gain describes how an antenna concentrates energy in a particular direction compared to the power you put into the antenna. It is basically the ratio of the power that is radiated (in the direction you care about) to the input power, which reflects how efficiently the antenna converts input power into radiation in that direction (and, in receive mode, how effectively it captures energy from that direction). In other words, gain is the product of directivity (how narrowly the antenna can beam energy) and efficiency (how much of the input power is actually radiated or received).

This depends on the antenna’s design, so gain isn’t the same for every antenna and isn’t independent of design. It also applies to both transmitting and receiving, not just one.