This communication presents an improved method for reducing radar cross section (RCS) using dielectric-barrier-discharge (DBD) air plasma. By integrating a patterned dielectric layer in the region where plasma is generated, the effective permittivity is increased. This leads to higher electron density and induces a higher power absorption, enhancing the RCS reduction without altering the plasma generation conditions, such as bias voltage or gas. With an optimally designed dielectric pattern, the experimental results for a $200\,\, \times 200$ mm2 conductor plate show a 1.2-fold increase in absorbed power, resulting in up to 34.7 dB of RCS reduction in the 8.0–10.0-GHz range, which is a 10.7-dB improvement compared with without the patterned dielectric. This technique has achieved the largest RCS reduction reported so far for plasma-based methods, establishing it as one of the most effective approaches for RCS reduction.