Theory and Design of a Cylindrical Ferrite Resonator Antenna Using ${{\mathrm {HE}}}_{ {11\delta }}$ Mode Splitting Behavior

Abstract

A theoretical model of a cylindrical ferrite resonator antenna with a dc magnetic bias, applied in the direction parallel to the antenna height, is proposed. ${\mathrm {HE}}_{\mathrm {11\delta }}$ mode splitting behavior caused by tensor nature of the permeability of a biased ferrite is investigated. The proposed model is validated through an experimental investigation of the HE $_{{\mathrm {11\delta }}}$ mode antenna. This communication utilizes a Li-ferrite suitable for the antenna applications. The presented theory is shown to correlate well with the measured results. It is also found that HE $_{{\mathrm {11\delta }}}$ mode splitting behavior of the antenna involves frequency and polarization, and bandwidth tuning performances. Therefore, the antenna is a good candidate for a multifunctional antenna.