Hybrid Modes in RDRA

Abstract

In this chapter, new kind of resonant mode, i.e., hybrid mode in RDRA (rectangular dielectric resonator antenna), is described using mathematical modeling. RDRA is excited by inserting RF feed probe or microstripline having finite dimensions, carrying electric and magnetic currents at a given frequency. The charge conservation equations then imply the presence of electric charge densities and magnetic charge densities within the resonator. From Maxwell’s equations, we derive vector Helmholtz equations for the electromagnetic fields. The vector sources provide electric charge which gets converted into magnetic charge. In one of the models, sidewalls of the resonator are perfect magnetic conductors, and top and bottom surfaces are perfect electric conductors. Thus, the boundary conditions on the fields are such that the tangential components of the magnetic field vanish on sidewalls and the normal components of the magnetic field vanish at top and bottom surfaces. The normal components of the electric field vanish on sidewalls. H _z can therefore be expanded as linear combinations of sin functions in x y direction along with z-component of the source. For the H _z , Helmholtz equation can be expanded in terms of sin functions (assuming that these sources vanish on boundary), with z-dependent coefficients.