COMPACT EPSILON NEGATIVE ZEROTH-ORDER RESONATOR ANTENNA WITH HIGHER RADIATION EFFICIENCY

A novel zeroth-order resonator (ZOR) antenna is presented, which comprises one unit cell of epsilon negative (ENG) structure. Its Q-factor is decreased by introducing a series capacitor to the shunt branch of the unit cell and reducing the shunt capacitive effect of the ENG structure as well, thus higher radiation efficiency is obtained with very small size of only 9.8 mm x 14.75 mm (0.058 lambda(0) x 0.087 lambda(0) at 1.78 GHz). A prototype is fabricated and measured, and the experimental results show that the novel ZOR antenna can achieve a bandwidth of 25 MHz, monopole-like radiation pattern, gain of 1.30 dBi, and efficiency up to 78%. (c) 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:897-900, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25857