In the process of assessing the requirements for radio frequency (RF) or microwave energy absorption in any particular application, one needs to know several key pieces of information.

Perhaps the first thing to know, is the location of the absorber with respect to the antenna or emitter. Is it in the near field or far field? The definition for this is well documented in the literature; but it basically deals with whether the emanating wave front is sufficiently far from the source to be flat enough to conform with the planar math equations.

We have included a calculator in the tool box to assist in this determination. The information that you will need is the frequency of interest and the principle dimension of the antenna.