How to Convert Flux Density to Antenna Power
- 1). Using an electronic instrument known as a field probe. There are other, more complicated ways of measuring the power flux density, but for our puroposes, a field probe will suffice.
As an example, assume the power flux density was measured to be 20 Watts per unit area -- W/m^2, which is the unit of measurement of power flux density -- at a distance of 3 meters from the antenna. - 2). Calculate the spherical area around the antenna.
In our example, if the power flux density is measured at 3 meters from the antenna, then the area is 4 multiplied by the constant pi -- multiplied by the distance from the antenna squared (multiply the radius by itself). This results in an area of 113.10 meters squared (m^2). - 3). Multiply the power flux density by the spherical area.
In our example, multiplying 20 W/m^2 by 113.10 m^2 gives 2261.9 Watts. This is the antenna power.
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