  This paper investigates the radiation properties of two coupled split-ring
resonators (SRRs). Due to electromagnetic coupling, two hybrid magnetic plasmon
modes were induced in the structure. Our calculations show that the radiation
loss of the structure was greatly suppressed by the hybridization effect. This
led to a remarkable increase in the Q-factor of the coupled system compared to
the single SRR. By adjusting the distance between the two SRRs, the Q-factor
changed correspondingly due to different electromagnetic coupling strengths.
This resulted in a coupled structure that functioned as a new type of
nanocavity with an adjustable Q-factor.
