Kunihiko Nakajima

Low-Loss Transmission Characteristics of Transparent Conductive Thin Films in GHz Range

The resistivity of transparent conductive thin film formed by sputtering exhibits a dependence on film thickness. In this study, an analysis by electromagnetic field simulation of resistance effect on the transmission characteristics was carried out. The overall resistance of the signal waveguide governs the transmission characteristics, and variation of the resistance at the interface between the substrate and the thin film has no significant effect. We evaluated a structure in which fine metal wiring that is not visible to the eye is placed on transparent conductors to reduce the resistance of the transmitting waveguide. Electromagnetic field simulations suggest that this structure improves the transmission characteristics while keeping high transparency.

Electric property of ZnO based transparent conductor films in GHz range

Newly developed transparent transmission line structures using ZnO film and fine metal wiring that is not visible by eye have been designed. In this paper, some electromagnetic field simulations suggest that the structure improves transmission characteristics while keeping high transparency. It was revealed that the reflection characteristic of a new transparent coplanar waveguide (CPW) could be improved and the characteristic impedance was controlled well by the width of signal line of ZnO film.