Modeling of antenna array mounted on platform with multi-region domain decomposition method

Abstract

The performance of antenna working on aircraft is usually affected by the presence of platform. Platform may perturb the antenna pattern, distort the near field distribution and provide coupling path between multiple antennas on platform. To comply with the requirement on radar signature and areodynamic performance, antenna on the aircraft usually resides inside aperture. Simply simulating the antenna in freespace or on infinite ground plane will not result in satisfactory accuracy in this case. In this contribution, a Vivaldi antenna array mounted inside an aperture of platform is analysed, the geometry can be found in Fig. 3. The antenna region (i.e. the antenna array and its surrounding part of platform), is first analysed with multi-region domain decomposition code proposed in [2]. Instead of modeling the entire region with pure FEM-based domain decomposition, we decompose it into antenna array sub-region and open-cavity sub-region, for which FEM and BEM solver are applied respectively. The two sub-regions are disjointed and they are coupled with Huygens principle, so that the air volume between two regions can be excluded from computational domain. To enhance the convergence, Krylov subspace solver is implemented in the outer loop. The result shows that Krylov solver gives a faster convergence than Gauss-Seidel (GS) solver. With the full-wave solution of antenna region obtained, we employ the high-frequency method to calculate the antenna pattern with the effect from the entire platform.