Influence of magnetic material on dielectric resonator antenna excitation

Simulated data is presented to illustrate previous analytical results for hemispherical dielectric resonator antennas (DRA) composed of both dielectric and magnetic material. The bandwidth and radiation efficiency is significantly increased when μ_r=ε_r while minimum electrical size requires compatible boundary conditions (CBC) for either probe or slot excitation. Simulated data for various shapes of rectangular DRA, including offset feeds, confirm that CBC again dictate electrical size while equality of μ_r and ε_r remains a design guide for maximum bandwidth and efficiency. The μ_r/ε_r ratio is also seen to be a useful design parameter for dual-mode DRA to achieve a wide bandwidth. It is concluded that the incorporation of ferrite material will significantly enhance DRA performance, given the availability of appropriate material.