BANDWIDTH ENHANCEMENT OF EPSILON NEGATIVE ZEROTH-ORDER RESONATOR ANTENNAS USING A Co_2Y HEXAGONAL FERRITE HELICAL LOADING

摘要

A method to extend the bandwidth of epsilon negative (ENG) zeroth-order resonator (ZOR) antennas using a Co_2Y hexagonal ferrite (Ba_2Co_1Zn_(0.7)Cu_(0.3)Fe_(12)O_(22)) is presented. It is accomplished by using the ferrite helical loading for shunt inductance of ENG ZOR unit cell. The Co_2Y hexagonal ferrite has been developed for performance improvement of mobile handset antennas. The permittivity of the developed Co_2Y hexagonal ferrite is about 9.3, and the permeability is about 4. An ENG ZOR antenna based on simplified planar mushroom structure unit cell was fabricated, and bandwidth enhancement and good radiation performance were achieved.