Electromagnetic behaviour of flexible substrates with meshed and conductive films ground planes

Abstract

In this work the electromagnetic performance at high frequency of flexible substrates with meshed and conductive film ground planes is compared with that of flexible substrates with unmeshed (solid) ground planes. Several types of specially designed structures have been studied - mesh ground, conductive film ground and solid copper ground. The conductive film used in this work is based on Tatsuta silver film which is developed especially for flex interconnects to be used in hinge applications in smart phones, and LCD drivers. The flat and bend cases of the flexible substrate are also compared and reported in this work. The comparison is done in frequency domain as well as in time domain through simulation. The structures are compared in terms of their far-field radiation as well as near-field coupling. The simulations have shown that the meshed and conductive film ground will affect the near-field coupling and the loss of the transmission structures but there is little difference in terms of radiating field.