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A new concept of radio frequency (rf) driven atmospheric pressure dielectric barrier discharge source based on printed circuit board (PCB) is proposed for efficient and uniform large area processing of polymeric surfaces. The source comprises a perforated PCB with a metal electrode and an optional metallic (Cu) grid on its two surfaces. The source was characterized using electromagnetic simulations and electrical measurements. Different source configurations were compared concerning the existence of a Cu grid into the PCB configuration and also the cases of grid being powered or floating. Electric field simulations showed enhanced electric field peak values with the grid addition, especially for the powered grid configuration, and also high electric field uniformity over the discharge area. The electrical measurements in helium plasma confirmed that the grid existence resulted in lower breakdown voltages and higher power dissipation. Etching rate and water contact angle measurements in plasma treated poly(methyl methacrylate)/PMMA films were performed to evaluate the source efficiency in polymer processing. The etching rate increased almost two times in the presence of a grid, reaching values around 65 nm min−1 in pure He. An optimum water contact angle of 27.4° was achieved after plasma treatment with the powered grid source and this value increased to 33° after four weeks of storage indicating the enhanced hydrophilization stability.