Magnetic loading of artificial magnetic conductors for bandwidth enhancement

A magnetically loaded artificial magnetic conductor (Mag-AMC) providing enhanced bandwidth has been developed. The design is a variation of the Sievenpiper (Ph.D. diss., UCLA Elec. Eng. Dept., 1999) "thumbtack" structure, which makes use of a low-loss, aligned, barium-cobalt hexaferrite material in the spacer layer. The design has been carefully engineered to align the high impedance and surface wave bandgap frequency bands. The demonstrated result is greater than four times improvement in bandwidth relative to a conventional structure of the same thickness. Using this Mag-AMC it is possible to build an antenna to instantaneously cover the UHF LOS frequency band in a depth of about 1.5".