Transparent films for electromagnetic shielding of plastics

The interest in the development of lightweight transparent electromagnetic (EM) shields for the radio frequency range has been growing up in the last years together with the expansion of the electronic market and the increasing use of plastics. Example of industrial applications are video displays of electrical and electronic apparatus, of electromedical devices, of portable electronic equipment. Applications in the aerospace sector are also very attractive, such as in protecting the electronic systems of aircrafts from the high-intensity electromagnetic fields emitted by radio emitters, TV, radars and telecommunication systems. Moreover, the recent limits of radio frequency electromagnetic fields suggest the use of transparent shields for building windows. Thin films can provide an effective solution in EM shielding of plastic substrates or enclosures. In particular, the use of 1-D photonic band gap structures named as 'transparent metals' has been recently investigated and tested for EM shielding applications in the radiofrequency range, by using physical vapor deposition technique. In this work, the design method and the technological issues concerhing the realization and electromagnetic testing of the shields will be described. Some recent results will be presented, and both perspectives and limits of the proposed technique will be discussed and compared with other solutions.