A simple MATLAB program to calculate the electric field levels in the near field of a monopole antenna

The Space Shuttle can carry a variety of payloads into Earth orbit to be used in a number of scientific experiments. Many of these payloads use simple monopole antennas to provide for command and telemetry communication. In one future mission, a payload will use two monopole antennas to support communications links at 145.8 MHz and 436 MHz, respectively. For crew safety during extravehicular activities (EVAs), a keep-out zone must be determined, beyond which the astronauts must stay, in order to keep them safe from the effects of RF exposure to themselves and their EVA equipment. Thus, the strength of the electric fields radiated by each antenna as a function of distance from the antenna must be calculated. To achieve this, a program was written in MATLAB, based on well known relationships for radiated fields. MATLAB was chosen since it afforded the ability to output the results in any desired format. The results obtained by the MATLAB program were then compared to those obtained by a numerical method of moments program, NEC2, and good agreement was found to exist between the two methods.