Superconducting power cables with high capacity and high efficiency are regarded as a key technology to realize the next-generation power networks. Coated conductors (CCs) have been extensively used to develop such cables, particularly more than 4+ mm-wide CCs. Recent research shows that narrow CCs (e.g., 2 mm) prove to have a pronounced advantage on cable ac loss reduction. Besides, thanks to laser cutting technique, it becomes possible to cut wide CCs into narrow strips without considerable damage. Hence, narrow CCs are attracting more and more attention and have turned into a practical option for developing more efficient superconducting cables. However, studies on cables with narrow CCs are far from sufficient. This paper is to clarify the dependence of ac loss characteristics on structural compactness in superconducting cables consisting of narrow CCs. A set of numerical models have been developed on the 2D FEM method to simulate both monolayer and multilayer cables including 1-, 2-, 4-, and 6-layer cables. The former three types are practical cables currently under development and the last one is a future option for ultrahigh power transmission. Narrow CCs with the same critical current were selected for all the cables that are designed with various structures from compact to loose configurations. Within these cables, numerical electromagnetic analysis has been carried out to study and clarify how their loss characteristics are affected by structural compactness.