I need to compute a beam footprint, but I know only the frequency of the beam.

How can I compute the footptint?

  • 3
    \$\begingroup\$ You can't, just knowing the frequency. You also need to know the beamwidth or antenna pattern, and some geometry information such as the angle between the antenna beam and the ground (target), sometimes called the grazing angle. \$\endgroup\$
    – SteveSh
    Oct 29, 2021 at 12:44
  • 2
    \$\begingroup\$ Normally you'll have an antenna pattern, with a small correction for frequency, and a big correction for angle of the ground. An antenna pattern can be anything from isotropic to a very tight spot beam indeed. \$\endgroup\$
    – Neil_UK
    Oct 29, 2021 at 12:57

1 Answer 1


You need to characterize your antenna in a test center.

Take a look here:


  • \$\begingroup\$ That gives you the antenna (beam) pattern, but does not tell you anything about what that looks like when it strikes the ground, except in the pathological case of the beam hitting the ground at a 90 deg angle. \$\endgroup\$
    – SteveSh
    Oct 29, 2021 at 19:37

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