To study electromagnetic scattering by vehicle above ground,a half-space multilevel fast multipole algorithm (MLFMA) is proposed.Near terms in the MLFMA are evaluated by rigorous half-space dyadic Green functions.Far MLFMA interactions employ an approximate dyadic Green function via a direct-radiation term plus a single real image.The real image method leads to fast and convenient computation compared with the discrete complex image method (DCIM).It also results in less memory requirement and CPU time.Finally,bistatic radar cross sections are shown for a realistic 3D car model over lossy ground.

In order to solve EMC problems for multiple antennas mounted on airborne platforms with limited computer resources, a multilevel fast multipole algorithm (MLFMA) with adaptive number of levels is implemented based on Electric Field Integral Equation(EFIE). For the analysis of coupling between antennas, more reasonable arbitrary isolation is adopted instead of traditional isolation. BiCGStab(l) combined with near-field preconditioner is employed which improves efficiency of the MLFMA. Radiation pattern and isolation of ultra-shortwave antennas on a full-scale Boeing 747 aircraft model are obtained and discussed.