It is known that, for the isolated dielectric cylinder waveguide, there exists the cutoff frequency ω * below which there are no guided (radiationless) modes. It is shown in the paper that the infinite plane periodic array of such waveguides possesses guided modes in the frequency domain which is below the frequency ω * . So far as the finite array is concerned, the modes in this frequency domain are weakly radiating ones, but their quality factor Q increases as Q(N ) ∼ N 3 , N being the number of the waveguides in the array. This dependence is obtained both numerically, using the multiple scattering formalism, and is justified within the framework a simple analytical model.