Microwave Properties of Co₂Ferrite for Miniaturization of Antenna

Abstract

-The sintering behavior and microwave properties of ferrite (Ba3Co2-2xZn2xFe24O41 ceramics) were investigated for microwave applications. Also PIFA type antenna with ferrite was simulated. All samples were prepared by the solid state reaction method and sintered at 1350℃. All ceramics had relatively density above of 92% compare with theoretical density of Ba3Co2Fe24O41 ceramics. From the XRD pattens, the Z-type phase was existed as main phase in Ba3Co2-2xZn2xFe24O41 ceramics. The permittivity and permeability of Ba3Co2-2xZn2xFe24O41 ceramics were increased with Zn additions and decreased rapidly over frequency of 200～600 MHz. Several PIFA type antennas with ferrite and FR4 were simulated. All antenna structure had return loss of less than -10 dB at each resonant frequency. Simulated antenna using both ferrite and FR4 showed size reduction of 25% without a significant decrement of efficiency.