The Effect of Subtractive Manufacturing Technologies on the UWB Antenna’s Scattering Parameter

The paper investigates the effect of commonly used subtractive manufacturing technologies on the scattering parameter of an Ultra-WideBand (UWB) antenna that was designed, realized, and measured. As a result, the conventional copper layer etching method using two chemical solutions based on ferric chloride and hydrochloric acid, as well as the Computer Numerical Control (CNC) machining, are critically analyzed. As proven by the obtained results, the etchant, its temperature, and the etching time has a direct effect on the quality of the realized UWB antenna’s edges. Along with the scattering parameter of the antenna, the cross sections’ analysis of the quality of the edges is presented. The Printed Circuit Board (PCB) with the copper layer was used in three thicknesses (17.5, 35, and 70 $\mu$m) for the experiments described in the paper. The polyimide film with a thickness of 50 $\mu$m was used as the substrate material. Due to the thin polymeric film and the narrow width of the feeding element (330 $\mu$m), CNC machining is at the limit of its possibilities. Additionally, the paper analyzes the effect of the etching solution’s temperature on the edge quality in the high frequency area.