Gain: Difference between revisions
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The gain of an antenna is the relative increase in radiation at the maximum point expressed as a value in dB above a standard. The standard to which other antennas are compared is usually a ½-wavelength dipole. The standard antenna is given a reference gain of 0dBD (zero decibel referenced to dipole). This comes from: | The gain of an antenna is the relative increase in radiation at the maximum point expressed as a value in dB above a standard. The standard to which other antennas are compared is usually a ½-wavelength dipole. The standard antenna is given a reference gain of 0dBD (zero decibel referenced to dipole). This comes from: | ||
<math> \mbox{gain} = 10 \times log \left( \frac {Pe}{Pi} \right) </math> | <math> \mbox{gain} = 10 \times \log \left( \frac {Pe}{Pi} \right) </math> | ||
Where '''Pe''' is effective radiated power and '''Pi''' is input power | Where '''Pe''' is effective radiated power and '''Pi''' is input power | ||
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Pe = 3, Pi = 1 | Pe = 3, Pi = 1 | ||
<math> 10 \times log \left( \frac {3}{1} \right) = 4.77\mbox{dBD} </math> | <math> 10 \times \log \left( \frac {3}{1} \right) = 4.77\mbox{dBD} </math> | ||
Revision as of 00:41, 6 August 2008
What is Gain?
The gain of an antenna is the relative increase in radiation at the maximum point expressed as a value in dB above a standard. The standard to which other antennas are compared is usually a ½-wavelength dipole. The standard antenna is given a reference gain of 0dBD (zero decibel referenced to dipole). This comes from:
<math> \mbox{gain} = 10 \times \log \left( \frac {Pe}{Pi} \right) </math>
Where Pe is effective radiated power and Pi is input power
An antenna with the effective radiated power of three times the input power would therefore have a gain of:
Pe = 3, Pi = 1
<math> 10 \times \log \left( \frac {3}{1} \right) = 4.77\mbox{dBD} </math>