The radiation and scattering properties of the split-ring and other resonators

In this paper we consider the fundamental radiation and scattering properties of the split-ring resonator (SRR) and compare these to the radiation and scattering properties of other resonators that are based on both dipole and loop structures. We show that as ka→0, the SRR radiates as an electric dipole not a magnetic dipole. In the receiving or scattering mode, like all antennas or scattering elements, the SRR responds to both the incident electric and magnetic fields. That is, it does not have an independent response to only the incident magnetic field. Furthermore, as a scatterer, the SRR will only behave as a magnetic dipole when ka→0 and where it is resonated with capacitance, in which case its configuration is simply that of the well-known small tuned loop resonator.