Miniaturized UHF Band Microstrip Antenna Designed with Spiral Metamaterial Inclusions

A miniaturized microstrip antenna is designed with spiral metamaterials for the UHF band applications. One numerical demonstration shows that a metamaterial antenna with patch size of 80mm×80mm resonates at 818MHz. The electrical patch length is only 0.221λ, much smaller than the 0.51λ for a traditional microstrip antenna. The small antenna is observed with a bandwidth of 2.9% and total efficiency 94.8%.