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I've recently written a program to predict power density around antenna for compliance with radiation limits. One of the parameters required for the program is antenna transmit power. Antenna transmit power is defined as the amount of power radiated by the antenna. The transmit power is proportional to the input or consumed power of the antenna.

Transmit Power = Efficiency * Input Power

Data sheets on antennas typically show the maximum consumed power per port but not efficiency. I realize power transmission efficiency is a combination of antenna efficiency, connector losses, and matching impedance. It would be nice to know if there is a way to estimate the antenna efficiency or transmit power based on the input power. Also I assume an antenna won't operate at its full rated power at all times. So what influences how much power an antenna consumes?

Here's some relevant information I found. That's a radiation compliance report. In their report on page 13 they stated that they ran their simulation using a transmit power of 20W. I looked up the antenna datasheet and the maximum power per port was 250 W-500 W (depending on frequency.)

How might they have come up with the 20 W for their simulation?

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"So how do you think they came up with the 20W for their simulation?"

I don't think it matters. The relative power density profile (antenna pattern) doesn't care what the input power is. However the absolute power density profile does. If you double the input power the power density at any given point doubles also.

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I'm not certain how you would go about this test other than to actually take power readings around all the transmit lobes on the antenna itself. I can say this: efficiency is directly related to the material of which the antenna is made. Copper is far more efficient than aluminum.

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    \$\begingroup\$ "efficiency is directly related to the material of which the antenna is made. Copper is far more efficient than aluminum". I don't think that's true. While copper is a better conductor than aluminum, that difference produces little change in the efficiency of the antenna, aside from ohmic losses. All of our antenna (elements) - notches, slotted waveguide, etc, are all made with aluminum. These are for very demanding applications where engineers would sell their mother to take out a half-dB of loss <kidding>. \$\endgroup\$
    – SteveSh
    Commented Jan 31, 2020 at 16:06
  • \$\begingroup\$ Yes, it is. How old are your engineers? \$\endgroup\$
    – Lee the Geek
    Commented Feb 1, 2020 at 22:24
  • \$\begingroup\$ What difference does that make? \$\endgroup\$
    – SteveSh
    Commented Feb 2, 2020 at 0:19
  • \$\begingroup\$ The difference it makes is that I have been engineering and building antennas since the mid 60s. I have the experience necessary to make my claim. \$\endgroup\$
    – Lee the Geek
    Commented Feb 3, 2020 at 15:35
  • \$\begingroup\$ Why don't you go on line and look at some state of the art antenna systems and see what their antenna elements (radiators) are made of. Original F-16 - aluminum slotted wave guide; AWACS - aluminum slotted wave guide. F-22, F-35, aluminum stepped notch. \$\endgroup\$
    – SteveSh
    Commented Feb 3, 2020 at 22:43

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