On EBG structures for cellular phone applications

Electromagnetic Band Gap (EBG) materials exhibit many interesting features for microwave and millimetre wave applications. Recently, the employment of such materials has been proposed for cellular phone applications in order to limit the backradiation and to prevent the exposure of the user from the electromagnetic field. In this paper, we first present a new way to synthesize EBG structures suitable for very compact layouts and then we apply the technique to verify the attractive features of EBGs in cellular phone applications. We show that the suppression of the surface waves, due to the high impedance behaviour of the EBG materials, does not avoid back-radiation from a cellular phone. Nevertheless, EBG structures permit to improve both the radiation efficiency and the impedance bandwidth of terminal antennas.