Characterization of cavity-backed conformal antennas and arrays using a hybrid finite element method with tetrahedral elements

A hybrid finite-element formulation has been proposed for characterization of the scattering and radiation properties of microstrip patch antennas and arrays residing in a cavity (Jin and Volakis, 1991). The technique combines the finite-element (FE) and boundary integral (BI) methods to formulate a system for the solution of the fields at the aperture and those within the substrate. In the previous implementation, rectangular bricks/patches were used for a discretization of the cavity volume/superstrate. These elements inherently limit the applicability of the method to rectangular shape patches and cavities, and to specific feed structures. To avoid such restrictions on the geometrical adaptability of the FE-BI method, the authors consider its implementation using tetrahedral/triangular elements for discretizing the cavity volume/aperture. The tetrahedral elements permit excellent geometrical adaptability. The characterization (scattering/radiation) of nonrectangular patches and broadband radiators is considered. The method's ability to model practical shape and corporate feeds is demonstrated and results are presented for the antenna/array radar cross section in and out of the operating band.<>