Electromagnetic Analysis for Miniaturized Patch Antennas With Self-Biased Ferrite Thin Films

An accurate electromagnetic analysis is carried out for a tunable miniaturized patch antenna loaded with a self-biased magnetic film. The patch antenna includes a lossy dielectric substrate and a layered ferrite-thin-film superstrate above microstrip. The loaded magnetic thin film is self-biased and is essential to enhance the property of the antenna. The entire structure is of highly multiscale and multimaterial feature, and the widely used surface integral equations (SIEs) may not be able to result in a well-conditioned impedance matrix if analyzed by the integral equation approach. We use volume-surface integral equations (VSIEs) to formulate the problem, and the VSIEs are solved by the method of moments with a different implementation scheme. The scheme keeps the dyadic Green's function in its original form without moving the del operator onto the basis function and testing function, so that nonconforming meshes at material interfaces can be allowed. Numerical examples are presented to illustrate the approach, and the good results can be observed.