Indian researchers evolve new tech to make military equipment less visible to radar

07 Feb 2023

In a significant achievement, Indian researchers have able to develop a material that can make stealth vehicles and covert establishments less visible to the radar. Radars are used in defence and civil sectors for surveillance, and navigation, to detect and track aircraft, ships, ground vehicles, and movements within covert establishments. The material can absorb a wide range of radar frequencies (signals), irrespective of the direction from which the radar signal hits the target, said the team of researchers at the Indian Institute of Technology (IIT), Mandi, which has developed the technology. According to it, it can also be used to cover windows or glass panels of stealth vehicles and covert establishments that must be invisible to radar. The research has been published in the journal "IEEE Letters on Electromagnetic Compatibility Practice and Applications". Being invisible to radar is a crucial defence strategy and the ability to evade radar detection can reduce the chances of being targeted by enemy weapons," explained Shrikanth Reddy, Assistant Professor, School of Computing and Electrical Engineering, IIT Mandi. "Any technique that makes things invisible to radar can also be used in the commercial sector to reduce radiation leakages from buildings and make them more secure. For example, invisibility to radar can also be used in private or covert establishments for the protection of information and privacy," he said. Radar Cross Section (RCS) reduction is a way to make something less visible to radar. RCS reduction is achieved by using materials that can absorb radar signals, or by shaping the object in a way that makes it difficult for radar to detect."We have developed a technology based on Frequency Selective Surface (FSS) that absorbs a wide range of frequencies used in radar, which makes the surface invisible to radar," Reddy explained. The proposed design uses an optically transparent Indium Tin Oxide (ITO)-coated Polyethylene terephthalate (PET) sheet. The FSS patterns are created on this PET sheet. PET sheet is a common thermoplastic that provides high dimensional stability, excellent mechanical strength and good resistance. The researchers created FSS pattern on the PET sheet with the laser engraving technology. Due to symmetrical and lossy nature of these patterns, the proposed material absorbs a wide range of electromagnetic (EM) wave frequencies within C (4-8 GHz), X (8-12 GHz) and Ku (26-40 GHz) Band. Tests showed that this technology can absorb more than 90 per cent of the radar waves in a wide range of frequencies. The team performed experimental studies on their design and the results matched well with the theoretical analysis, verifying its effectiveness. "This technology can be used on window or glass panels of stealth vehicles and covert establishments due to its optical transparent nature," Reddy said."The team has already developed a prototype and the results have been published in IEEE Journal. This technology has potential applications for RCS reduction and absorptionunwantedradiation leakages," he added.