A conformal UWB directional antenna

An experimental analysis of the conformal properties of an antipodal exponentially tapered antenna in the UWB range is presented. The ability to be conformal, due to a thin dielectric layer, allows the antenna to be curved in both the principal planes. With the antenna located in the YZ plane, this study considers the conformity for a fixed radius in the XZ and XY planes. The investigation includes numerical and experimental work on an empty and full water pipe, considering that the antenna can be placed on the surface of a flow meter system, like a water tank. Initially the planar free space antenna is compared with the conformal free space antenna; then the antenna is attached to the empty pipe and the pipe finally filled with water. The effect of the conformity has a small influence on the antenna performance, mainly seen as increased cross polar levels. The presence of the pipe affects the reflection coefficient without significantly degrading the UWB performances, but with a reduction of the efficiency. The close proximity to a lossy material in the case of the full water pipe shows a notable reduction in gain. It was observed that the water effect can be mitigated by shifting the antenna away from the pipe surface, guaranteeing good performance.