Development of planar devices using low-loss materials

As the importance of advanced microwave and millimeter-wave diagnostics increases, the fabrications of high-performance planar devices become essential. This paper describes the development of planar devices such as antennas using low-loss fluorine materials. The problems to be solved for the present purpose are the low degree of adhesion between copper foil and fluorine substrate and the accuracy of device pattern using conventional fabrication techniques. In order to solve these problems, surface treatment of fluorine films and a fabrication method using Electro-Fine-Forming (EF2) are proposed. The peel adhesion strength between the metal and the fluorine films and the value of dielectric constant of the fluorine films before and after grafting are reported. In order to confirm the performance of the treated films, microstrip lines are fabricated on the conventional fluorine substrates and on the grafted-PTFE (Polytetrafluoroethylene) films. The prototype antennas using fluorine substrates with EF2 fabrication technique are also introduced.