In this paper, we theoretically study optical responses of tightly-coupled terahertz metamaterial. Unlike loosely-coupled
one, tightly-coupled metamaterials exhibit resonant optical responses that are highly dependent on the interaction
between each unit resonators. In order to predict optical response and spectral behavior of effective parameters of the
metamaterials, a model based on coupled-mode theory is applied. Resonant optical response is shown to be highly
dependent on the gap-size between the resonators which relates to the inter-unit coupling, and we show that this
dependency implies the possibility of miniaturized metamaterials .