A film assembly or a multilayer stack can include an antenna having a spiral form disposed on a stretchable layer. The film assembly includes a stretchable substrate having opposite major top and bottom surfaces, and a first material disposed on the major top surface of the stretchable substrate in the form of a plurality of intersecting rows and columns making the film assembly less stretchable than the stretchable substrate. The rows and columns define a plurality of closed cells. An antenna for use in a radio frequency identification tag is disposed on the stretchable substrate in each closed cell and is isolated from the first material. The antenna includes an elongated electrically conductive electrode having a spiral form.