Integrated high-power THz arrays with beamforming ability can enable new applications in communication, sensing, imaging, and spectroscopy . However, due to the limited power-generation capability of a single source above the device fmax , efficient spatial power combining from multiple coherent sources becomes necessary to generate mW level of power. To create this 2D array of distributed frequency and phase-locked sources, prior works have shown central LO-signal distribution with local harmonic upconversion . However, this requires high power consumption in the LO distribution. In addition, phase-matching with PVT variations across the sources at the harmonic-radiating THz frequency can be quite challenging. A small θ perturbation at the fundamental frequency translates to Nθ at the radiated Nth harmonic, thus corrupting the array beam pattern. Another method to synchronize multiple distributed radiating sources (/2 spaced at Nfo) is through a mutual coupling network with active/passive elements in a coupled oscillator array , . However, the locking range in these methods is typically narrow (flocking f0/20 to f0/10) and PVT variations can easily cause desynchronization. In such a network, each cell is a self-sustaining oscillator, and the coupling network tries to establish injection signals to force synchronization between these individual free-running oscillators. In this paper, we used a 2D oscillating network with negative Gm(-Gm) cells at each node that do not oscillate individually but only collectively, establishing a robust frequency and phase distribution network across the chip for high THz-power generation. By making this network as the lowest layer, we can now separate the locking mechanism and the power-generation sources. This avoids loading and sub-optimal operation of the power sources. The distributed oscillating network at the lowest layer operates at 69.3GHz, and multi-layer local harmonic generation produces a radiated power of -3dBm and +14dBm EIRP at 416GHz in a 4×4 array.