Question
What is antenna efficiency?
Answer Options
- A) Radiation resistance divided by transmission resistance
- B) Radiation resistance divided by total resistance
- C) Total resistance divided by radiation resistance
- D) Effective radiated power divided by transmitter output
Correct Answer: B
Explanation
Antenna efficiency is a critical measure of how well an antenna converts the RF power fed to it into radiated electromagnetic energy. It determines how much of the input power is dissipated as heat (loss) versus how much is effectively radiated into space.
An antenna’s total input resistance (R_{Total}) is the sum of its radiation resistance (R_{Rad}) (the part of resistance that results in useful radiation) and its loss resistance (R_{Loss}) (the resistance that dissipates energy as heat). Antenna efficiency (η) is defined as the ratio of the power radiated to the total power input, which is calculated as Radiation resistance divided by total resistance: \eta = R_{Rad} / R_{Total} = R_{Rad} / (R_{Rad} + R_{Loss}).
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