Antenna gain of 10 dBi corresponds to what linear power gain factor?

• A. 2
• B. 5
• C. 20
• D. 10

Answer: (D)

Antenna gain in dBi uses a logarithmic scale to express how much power an antenna concentrates in its main direction compared with an isotropic radiator. To convert from dBi to a linear power gain factor, use G_linear = 10^(dBi/10). With a gain of 10 dBi, that becomes G_linear = 10^(10/10) = 10. So the linear power gain factor is ten, meaning the antenna delivers ten times the power in the main lobe relative to an isotropic antenna. For reference, a linear gain of 2 corresponds to about 3 dB, 5 to about 7 dB, and 20 to about 13 dB, illustrating how the decibel value maps to the linear factor.