New Stealth Material Could Push Military Advancements Beyond the U.S.

The ongoing war between Russia and Ukraine for nearly two years raises questions as to why Russia, the world’s second military power, can’t quickly subdue Ukraine, ranked 22nd globally.

The Russo-Ukrainian war has many external variables, such as support from other countries for Ukraine and international economic sanctions against Russia, making it difficult for either side to gain an outright victory.

Above all, the modernization of weapons, considered the most important in modern warfare, has a significant influence. In particular, the drones used by Ukraine in the early stages of the war directly hit Russian military supply routes, prolonging the war and undermining the morale of the Russian forces engaged in expeditionary warfare.

The Ukraine-Russia war and the Israel-Hamas conflict reaffirm the direction of modern defense capabilities. Future war victories will likely be determined by ‘stealth’ capabilities. It’s clear who the winner is in the fight between visible and invisible enemies.

Current military detection devices (radars) estimate the properties of an object (such as a fighter jet) by detecting the electromagnetic waves that bounce back after being radiated onto the object. The core of modern stealth technology is to minimize the amount of electromagnetic waves reflected when they hit an object.

The U.S. is currently leading in applying stealth technology to the military. The stealth technology used by the U.S. military involves applying paint to fighter jets to deflect (refract) electromagnetic waves.

The Wave Energy Extreme Control Research Team explains developing a metamaterial with stealth capabilities. ⓒWave Energy Extreme Control Research Team

Instead of Refraction, ‘Absorption’… Reduces Radar Electromagnetic Waves by 90%

The Wave Energy Extreme Control Research Team (CAMM), which has been researching metamaterials, has developed a stealth material that ‘absorbs’ electromagnetic waves instead of refracting them.

For reference, metamaterials are next-generation materials that implement properties not found in nature by creating artificial structures smaller than the wavelengths of electromagnetic waves and mechanical waves. It’s a way of changing or stimulating a material’s inherent properties (physical properties) to possess new properties. It’s a material tailored to the target object (sound wave, electromagnetic wave, ultrasonic wave, etc.) that you want to control by transforming the existing properties.

Recently, CAMM has developed a stealth material that absorbs microwave band electromagnetic waves as a film with a width and length of 30 cm each. This material can absorb up to 90% of radar waves. Wave absorption is a method of artificially adjusting the electromagnetic characteristics of a material according to the frequency to absorb the incoming electromagnetic waves and dissipate them as heat loss.

According to CAMM, the material, one of the new materials based on ‘graphene,’ absorbs microwave band electromagnetic waves. It is easy to produce using conventional conductive ink on a polyimide plastic substrate and is competitive in terms of material cost.

As it is a thin film, it can be inserted between existing materials without deformation on curves, etc. It is more than a fifth thinner than existing materials and can absorb more than 10dB of sound. As a result, it can be applied not only to the stealth function of fighter jet bodies but also to underwater sound-absorbing panels for submarines and mufflers.

CAMM’s experiment results show that it can absorb electromagnetic waves in a broader wavelength range than natural materials.

Choi Tae-in, a researcher who has served as the Deputy Director of the Defense Science Research Institute and the Director of the Korea Institute of Machinery and Materials, explained, “(Radar wave) 90% concealment means that we have completed the work that can be done at the research stage and are pushing for the use in the defense industry such as fighter jets and ships. If optimization research and supplementary research are conducted in the future, the concealment rate can be further increased.”

The stealth material developed by CAMM has recently entered the verification phase. In collaboration with the Navy, the stealth metamaterial will be installed on some warships for performance testing. The suitability for actual operating environments is being verified on these ships, and the effect of reducing the RCS applied to the ship is being analyzed separately. RCS refers to the Radar Cross Section, which shows how much an object reflects waves.

Lee Hak-joo, the head of CAMM, explained, “If you apply metamaterials, you can improve the performance of equipment developed with basic materials by 30~40%. The U.S. and Europe have been conducting research from the beginning and are currently developing it as a major research area.”

He emphasized, “Korea is developing comprehensive metamaterial design, fabrication, and testing technology centered on our research team, but it is difficult to carry out the next research project after government support ended last August. According to the national strategy, it is necessary to actively set metamaterials as a mid-to-long-term research and development project and continue research.”