Embodiments include a plasma processing tool that includes a processing chamber, and a plurality of modular microwave sources coupled to the processing chamber. In an embodiment, the plurality of modular microwave sources include an array of applicators that are positioned over a dielectric body that forms a portion of an outer wall of the processing chamber. The array of applicators may be coupled to the dielectric body. Additionally, the plurality of modular microwave sources may include an array of microwave amplification modules. In an embodiment, each microwave amplification module may be coupled to at least one of the applicators in the array of applicators. According to an embodiment, the dielectric body be planar, non-planar, symmetric, or non-symmetric. In yet another embodiment, the dielectric body may include a plurality of recesses. In such an embodiment, at least one applicator may be positioned in at least one of the recesses.