Multiband antenna loaded by metamaterial-based ZOR and CSRR with monopolar radiation pattern

We present a miniaturized multiband monopole antenna loaded by metamaterial (MTM) structures, namely zeroth-order resonator (ZOR) and complimentary split-ring resonator (CSSR). MTM structures are used to reduce the antenna size significantly. Moreover, each resonant frequency of the antenna can be tuned by changing the geometrical parameters of the associated MTM resonator. Showing the monopole-shape radiation pattern characteristics at all resonant frequencies, the proposed compact MTM antennas are suitable for vehicular applications.