Foldable and Stretchable Liquid Metal Planar Inverted Cone Antenna

Abstract

A mechanically flexible planar inverted cone antenna (PICA) for ultrawideband (UWB) applications is presented. It can be both folded and stretched significantly without permanent damage or loss of electrical functionality. The antenna is manufactured with a process in which conductors are realized by injecting room temperature liquid metal alloy into micro-structured channels in an elastic dielectric material. The elastic dielectric material together with the liquid metal enables bending with a very small radius, twisting, and stretching along any direction. Port impedance and radiation characteristics of the non-stretched and stretched antenna are studied in simulations and experiments. The presented antenna has a return loss better than 10 dB within 3-11 GHz and a radiation efficiency of > 70% over 3-10 GHz, also when stretched. Tests verify that stretching up to 40% is possible with maintained electrical performance. The presented antenna is useful for example for body-worn antennas and in applications in harsh environments where mechanical flexibility helps improve durability.