Graphene film blocks wireless signals
![graphene](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2014/02/960px-Graphene_free.jpg?fit=860%2C460&ssl=1)
A transparent film made of graphene (illustrated above) layered with quartz absorbed 90 percent of radio waves.
AlexanderAlUS/Wikimedia Commons
A transparent film made of graphene (illustrated above) layered with quartz absorbed 90 percent of radio waves.
AlexanderAlUS/Wikimedia Commons