‘Invisible’ shield developed to add stealth capability to military platforms

Vijay Mohan

Tribune News Service

Chandigarh, August 18

In a novel innovation, Indian scientists have designed a metal mesh structure to construct a transparent shield against electromagnetic interference (EMI). This ‘invisible’ shield can be used in various military stealth applications and can cover electromagnetic wave emitter or absorber devices without compromising aesthetics.

Besides the physical shape, reducing the electromagnetic signature, which includes radar waves and radio signals, is an important element for enhancing the stealth capability of a weapon platform.

These transparent and flexible EMI shields have been fabricated by scientists at the Centre for Nano and Soft Matter Sciences (CeNS) from metal meshes using the crack templating method and spray coating, which is pioneered in their laboratory. These can be used instead of a continuous film coating on the desired substrates or surface.

The CeNS team has developed a copper metal mesh on a polyethylene terephthalate (PET) sheet as its substrate, which is claimed to have exhibited a visible transmittance, a parameter of visible transparency, of about 85 per cent.

Instead of a continuous film coating of a metal like copper on any transparent substrate such as glass or PET, where transparency can be compromised, the CeNS team deposited metal mesh networks on the substrate, which covered only seven per cent of the substrate’s area. This metal mesh can be created on any desired substrates such as acrylic, polycarbonate, glass, etc. without compromising the conductivity of the electrodes.

This makes metal mesh transparent compared to the continuous metal film that covers the entire area of the substrate. A metal mesh is said to provide better electromagnetic shielding compared to the same thickness of the continuous metal film. The team’s findings, published in the journal ‘Bulletin of Materials Science’, showed remarkably high values for total EMI shielding.

“This invention has the potential to satisfy the huge demand for highly effective transparent and flexible EMI shields, which can cover electromagnetic wave emitter and absorber devices without compromising their aesthetics,” Dr Ashutosh K Singh, scientist working on this project at CeNS, said.

The team lead by Prof GU Kulkarni, along with his co-workers from CeNS and an industrial partner, Hind High Vacuum Private Limited, have set-up a semi-automated production plant funded by Department of Science and Technology’s Nanomission in the CeNS campus for production of transparent conducting glasses which shows the potential for transparent EMI shields as well.