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Antenna design for improving shielding effectiveness of a Humvee

Summary form only given. Electronic Attack (EA) antennas operating over HF and VHF frequency bands are physically quite large and their design pose a significant challenge for antenna engineers. An interesting approach for their concealment is to consider the vehicles' underbelly as a possible mounting location. The required output power of EA antennas can be a few hundred Watts; therefore they can produce strong electromagnetic (EM) radiation, which is dangerous for the crew members when antennas are placed on a vehicle. Because of that, it is important to make sure the exposure limits set by the Federal Communications Commission (FCC) are not crossed when these antennas and systems are operational. Previous studies have shown that the bottom antenna location has the lowest EM exposure inside the vehicle cabin, or granted highest Maximum Permissible Power (MPP) compared with the top and rear antenna locations.The purpose of this work is to show the design of an antenna operating in the desired frequency range, which has the advantage of concealment and lower EM exposure inside the cabin due to the placement on the bottom of the vehicle's platform. The results from extensive method of moments computational studies are thoroughly validated using the finite element method. Impact of antenna placement on antenna parameters including impedance, patterns, and efficiency is studied. The EM exposure inside the cabin is also analyzed and compared with other antenna locations on the vehicle. Electromagnetic interference (EMI) between the designed bottom antenna and other antennas on the same vehicle is also analyzed. Finally, effects of flat grounds including PEC, asphalt, dry sand and wet soil on the antenna performance are also evaluated.