A novel dish concentrator formed by a rotating array of curved mirror units with same size is proposed, and the mirrors in the array can be either parabolic or spherical. This concentrator has the advantages of simple manufacturing, low cost, and readiness for compact arrangement owing to the obstruction-free state between mirror units. Taking a concentrator with the typical aperture (width is D=10 m) as an example, the influences of mirror width d and dimensionless parameters on the optical performance of the concentrator in detail are analyzed by the ray tracing method. The dimensionless parameters include the ratio of the concentrator's focal length f₁=R₁/2 to its width D (i.e., f₁/D), the ratio of the parabolic mirror's focal length f_m to the radius R₁ of the rotating array (i.e., f_m/R₁), and the ratio of the spherical mirror's radius R_m to R₁ (i.e., R_m/R₁). The results demonstrate the application value of the new concentrator in concentrating thermal systems (high concentration ratio requirement) and concentrating photovoltaic systems (high flux uniformity requirement), and provide a basis for its design. The following observations can be made from the results. The plane receiver in the novel dish concentrator should be located at a reasonable position below z=f₁ to minimize the focal spot. Interception width of the focused spot reaches the minimum value at f_m/R₁=0.6 when parabolic mirrors are used, whereas it usually reaches its minimum value at R_m/R₁=1.0 when the mirrors utilized are spherical. The variation laws of the average local concentration ratio and the peak concentration ratio with the concentrator's geometric parameters are opposite to those of interception width. When parabolic mirrors are used, the average local concentration ratio and the peak concentration ratio can be as high as 2846.8 and 7107.0 respectively, whereas the corresponding interception width is only 88.3 mm. In the case of spherical mirrors, they can reach 3000.0 and 7800.0 respectively, while the corresponding interception width is as small as 87.5 mm. Therefore, the proposed concentrator is readily applicable to high-temperature concentrating thermal systems. When reasonable geometric parameters are chosen for the concentrator, it can always obtain a square focal spot with a highly uniform flux distribution, and its average local concentration ratio can reach 420, indicating that it also works well in high-power concentrating photovoltaic systems.