The cases for n = 2 and 3, and the "ideal" case put more energy into the area of the untapered main lobe than the untapered beam does. To avoid excessive broadening of the main lobe, as well as excessive heating of the transmitting antenna, larger tapers (for, say, n > 2) may not be desirable. An examination of the sidelobeswill, however, be necessary for a more thorough evaluation of the beam tapers under consideration. Sidelobe Levels and Exclusion Zones To protect surrounding populations from possible hazards of microwave exposure, a safe distance from the center of the beam must be maintained. The region within this distance is known as the exclusion zone. For a given P, and safety threshold, the exclusion zone radius depends on frequency and choice of beam taper. To estimate the exclusion zone radius, the approximate upper bound of the microwave beam intensity will be considered. This, in effect, connects the sidelobc peaks together. To find the upper bound of intensity, the following approximations to the Bessel functions will be used for large u [10]:
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