Near-Field Gain Simulations in Altair FEKO

MIL-STD-464D dictates field strengths greater than 5000 V/m in certain ranges of the frequency spectrum. Achieving these field strengths in the far-field region often requires unrealistically high input power -almost 10 MW in some cases- and thus requires testing to be conducted in the near-field region. To meet these field strengths, pyramidal standard gain horns are often used in electromagnetic compatibility (EMC) testing for their wide bandwidth, ability to generate high gain, and ability to tolerate large amounts of input power. Despite the high gain and high input power tolerance of these antennas, they still cannot achieve the required field strength in the far-zone and therefore must be used in the near-field (Fresnel) region of the antenna. Due to this, our group has placed an increased focus on modeling the near-field gain of pyramidal horn antennas in commercially available EM solvers as well as analytically calculating the near-field gain in MATLAB. This issue and the subsequent analysis of similar pyramidal standard gain horns are examined in detail in (Carroll et al., Near-Field Analysis of Pyramidal Standard Gain Horns) which is submitted to the 2025 IEEE APS conference. In this paper, the Narda 646 standard gain horn is examined.