Analysis of conformal antennas on a complex platform

Modern aircraft are usually equipped with many antennas. To reduce the radar signature and the adverse effect on the aerodynamic design, the antennas are often conformal to the surface of the aircraft and sometimes embedded in a layered dielectric medium. Placing these antennas on an aircraft inevitably introduces distortion in their radiation patterns and causes mutual coupling, both of which affect the expected operation of the antennas. Therefore, it is important to develop accurate numerical prediction tools to characterize the radiation patterns and mutual coupling of antennas mounted on a complex platform. We present a novel hybrid technique to deal with this complex problem. This technique is based on a finite element-boundary integral (FE-BI) method (Liu, J. and Jin, J.M., IEEE Trans. Antennas Propag., vol.49, p.1794-806, 2001). It employs higher-order vector elements to model complex geometries accurately and reduce the number of unknowns for large-size problems and incorporates a highly effective preconditioner (Liu and Jin, IEEE Trans. Antennas Propag., vol.50, p.1212-21, 2002) to accelerate the convergence of the iteration solution of the FE-BI system and the multilevel fast multipole algorithm (MLFMA) (Song, J.M. et al., IEEE Trans. Antennas Propag., vol.45, p.1488-93, 1997) to speed up the evaluation of boundary integrals.