Optimization of patch antennas on ferrite substrate using the finite element methods

The nonreciprocal properties of ferrites have been used to control printed circuits and antennas. The material properties of ferrites are mainly controlled by the direction and strength of an externally applied magnetic field, thus enabling control of various antenna radiation and scattering characteristics. These unique properties of ferrite materials provide many desirable features such as tunability, polarization diversity, beam steering, and radar cross section (RCS) control. On the other hand, because of the additional variables such as bias field, bias direction and saturation magnetization, use of an optimization method is suitable for ferrite antennas to obtain the desired performance. We study the effect of a biased ferrite substrate on resonant frequency tuning and beam steering of patch antennas. The tools used are the gradient-based optimization methods in conjunction with finite element boundary integral (FE-BI) methods. The use of design optimization methods greatly facilitate the selection of "best" antennas. Compared with traditional antenna designs, the optimization processes not only decrease the simulation time, but also save on huge hardware manufacturing costs with the removal of expensive trial and error processes.