Transparent 0° phase shifter using micro-metal mesh conductive film

The design of a novel transparent 0° phase shifter (PS) using a proprietary self-assembling nano-particle technology-based micro-metal mesh (MM) conductive film is presented. The transparent MM conductive film has a sheet resistance of 0.7 Ω/sq and a visible-light transmission of 75%, resulting in high transparency and good conductivity. The proposed transparent PS is placed on a 2 mm-thick glass substrate of dielectric 5.7 and designed to operate at 2.45 GHz. A layer of MM film placed at the back of the glass serves as a ground. The transparent PS delivered a measured phase shift of 2.5°. The transparent PS can be used as a building block for realising a transparent Butler matrix (BM) beam forming network for inter/intra-vehicle wireless communication in the intelligent transport system. Besides being transparent, the proposed PS has a 0.25 mm profile excluding the glass substrate. These advantages greatly enhance the PS´s potential to be used also as a BM building component that can be mounted onto the glass surfaces of buildings for future fifth generation (5G) indoor wireless communications.