ABSTRACT Frequency selective surfaces (FSS) are periodic structures that transmit or block specific frequency components of electromagnetic waves. While the design of a single unit cell determines the fundamental frequency response of these surfaces, the arrangement of these cells into larger structures provides the desired filtering effect over wide surface areas. Low‐profile Doppler radar sensors are cost‐effective systems that measure the velocity of moving targets based on the Doppler effect. However, these sensors are prone to measurement errors, particularly at short ranges, due to factors such as multipath reflections, environmental noise, and signal attenuation. In this study, the integration of FSS structures with a low‐profile Doppler radar sensor operating at a center frequency of 10.525 GHz is investigated. An FSS unit cell with “square ring slot” geometry is designed, and single‐ and double‐layer arrays are constructed. The study involves simulation‐based modeling and experimental validation. The results demonstrate that the use of FSS enhances the Doppler radar's detection range and significantly improves measurement accuracy, particularly in the 1–2 m range. While the average error in Doppler sensor measurements was 35%, the double‐layer FSS configuration reduced the mean error to as low as 10%. This study reveals that FSS integration is an effective method for improving the reliability of Doppler radar sensors in short‐range applications and provides a significant contribution to enhancing the performance of sensor systems.
Kasar et al. (Wed,) studied this question.