Random Modulation Effect on CFAR Detection Using Active Frequency Selective Surface

Active frequency selective surfaces (AFSSs) can dynamically manipulate electromagnetic (EM) waves by amplitude modulation. This work researches into the effect on CFAR detection when a radar captures signals modulated by AFSSs fed by random coding electrical biasing. Three types of CFAR detection algorithms: cell averaging CFAR (CA-CFAR), order statistic CFAR (OS-CFAR) and censored mean level CFAR (CML-CFAR) are selected for presenting the modulation effect. The random modulation model with AFSSs is established and analysis for key parameters are carried out. Simulation results shows the modulation can reduce the peak amplitude over of the matched filter and increase the background-level by 4-8dB around the target position in all three CFAR detection algorithms. The coverage with the increased background-level can be controlled by the code rate of the random modulation which is in accordance with the theoretical analysis.