In this paper, decentralized static output feedback is considered for a class of dynamic networks with each node being a nonlinear system with infinite equilibria. Based on the Kalman-Yakubovich-Popov (KYP) lemma, linear matrix inequality (LMI) conditions are established to guarantee the stability of such dynamic networks. Furthermore, an interesting conclusion is reached: the stability problem for the whole Nn-dimensional dynamic networks can be converted into the simple n-dimensional space in terms of only two LMIs. A concrete application of output stabilization of coupled phase-locked loop networks is used to verify the effectiveness of the proposed methods.