Multiple Antenna InteractionsMay 17th Fact-of-the-Day
Because it is somewhere between difficult and impossible to design single antennas that have optimum characteristics over multiple frequency bands, it is common to install multiple antennas to support multiband operation. It often is assumed that each antenna will function as it would if installed separately. However, except for symmetrically-positioned, cross-polarized antennas or antennas spaced several wavelengths apart that usually is not true. An antenna modeling program such as MMANA can be used to estimate the radiation pattern effects of multiple antennas on each other by modeling all the antennas and their supporting structures and then driving the antennas one at a time. Pattern effects are difficult to predict without use of such a tool, especially where several antennas mutually couple, because of complex interactions. If you haven't modeled multiple antennas that way before, you may be surprised to find your antenna radiation patterns are rather different than you have thought. ©2005 Martek International All rights reserved.
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