This paper proposes a concept of invisible transmission line. Proposal is a kind of improvement technology for electric strong-coupled wireless power transmission system. Two adjacent dipole antennas have strong-coupled condition. In this situation, two independent coupled electric fields in opposite directions are occurred between each two charged poles of antennas. The independent fields have an important role on wireless transmission and behave like an almost invisible pair metal wire. Based on this idea, new type of metal plate dipole antenna is designed and developed. The main purpose of the antenna is to get relatively high transmission efficiency and to install radiation control function for practical use. The prospect got a higher efficiency was obtained in circuit simulations. But the results of electromagnetic simulations and experiments were not expected on efficiency. It was confirmed that the proposed control mechanism works well in the antenna system. This paper has described about wireless power transmission mechanism in a different viewpoints to conventional.