A new metamaterial unit cell for compact microstrip circuit designs

In this paper, a new metamaterial (MTM) unit cell implemented in a microstrip transmission line configuration is proposed. The new MTM unit cell, based on split-ring resonators (SRRs) is electrically small. The unit cell avoids the use of vias, and requires only single level processing. By tuning the physical parameters of the resonator structures, strong magnetic coupling between microstrip line and rings emerges at the resonant frequency of SRRs. This impedes signal propagation in the proximity of the resonant frequency. A compact X-band power divider is designed to validate the practical use of the new unit cell. While maintaining similar performance, a 71% reduction in impedance transformer is achieved in comparison to a conventional design.