Abstract <p>The impact of an active screen cage into a helium–nitrogen (He–N₂) radiofrequency (RF) plasma discharge has been systematically investigated using optical emission spectroscopy. In this regard, the key plasma parameters including emission intensity, electron temperature, and electron density were evaluated across a range of gas composition ratios, operating pressures, and RF power levels. The inclusion of the active screen cage consistently enhanced plasma performance, leading to increased electron concentration within the discharge, higher emission intensity, and elevated energy levels. These improvements are attributed to enhanced confinement and modified electric field distributions introduced by the cage geometry, which collectively facilitate more efficient excitation and ionization processes. Optimal plasma activity was observed at a He : N₂ ratio of 10 : 90, a pressure of 3 mbar, and elevated RF power, conditions under which Penning effects and energy retention in the plasma are maximized. These results highlight the effectiveness of active screen configurations in tailoring plasma characteristics, offering significant potential for applications in surface engineering, thin film deposition, and plasma-assisted materials processing.</p>