Demonstration of Impedance Matching Using a mu-Negative (MNG) Metamaterial

A mu-negative (MNG) metamaterial hemisphere was used to demonstrate impedance matching for a magnetic loop. The metamaterial was comprised of copper spirals deposited on an alumina substrate. The spirals, hemisphere, and magnetic loop were designed to operate at ~450 MHz. The effect of the metamaterial hemisphere was to improve the match of the electrically small loop antenna to the power source impedance increasing the overall radiated power. Results show a 17-dB increase in total radiated power relative to the bare loop. This was lower than anticipated due to losses in the MNG hemisphere.