A new on-chip light source configuration has been proposed, which utilizes the interaction between a microwave or laser and a dielectric nanopillar array to generate a periodic electromagnetic near-field and applies periodic transverse acceleration to relativistic electrons to generate high-energy photon radiation. The dielectric nanopillar array interacting with the driving field acts as an electron undulator, in which the near-field drives electrons to oscillate. When an electron beam propagates through this nanopillar array in this light source configuration, it is subjected to a periodic transverse near-field force and will radiate X-ray or even γ-ray high-energy photons after a relativistic frequency up-conversion. Compared with the undulator which is based on the interaction between strong lasers and nanostructures to generate a plasmonic near-field, this configuration is less prone to damage during operation.