A feasibility study in state-of-the-art multi- and monomode microwave cavities was conducted to outline important functionalities necessary in a microwave setup for continuous fine-chemicals synthesis. For multimode operation, the heating efficiency depends on the position as well as on the volume distribution of the load. For monomode operation, the heating efficiency does not depend on the axial position and has a maximum with respect to the load diameter. Based on this study, a microwave setup consisting of four cavities was designed and constructed. The setup provided a defined microwave field pattern and allowed focusing of the microwave power. A near-uniform distribution of microwave energy in all four cavities of the setup was achieved at reduced grid to applicator losses.