We focus on developing an effective Direction Of Arrival (DOA) estimation method for wideband sources based on the super-resolution concept. In this letter, we represent the data model of a wideband DOA estimation problem in a new form. Then, using this model, we propose an atomic norm minimization problem that leads to an accurate wideband DOA estimation method with no need for any focusing matrices. Moreover, this method requires no initial estimate and can be implemented by non-uniform linear arrays. Numerical simulations show that in comparison to some well-known techniques, the proposed method generates outstanding accuracy and higher robustness to noise. The effectiveness of the method is also verified in presence of close adjacent sources.