| The official commercial use of 5G communication technology has led to unprecedented development of wearable antennas in portable smart electronic devices.Wearable antennas based on liquid metal can keep the antenna conformal to the human body without losing its electrical properties,which has become a hot research topic.The dual properties of solid state and liquid state provide new requirements for the packaging process of liquid metal.In this paper,through the theoretical research,design and processing of liquid metal-based wearable antennas,two processing techniques for liquid metal-based wearable antennas are proposed,which provide new opportunities for future applications of liquid metal in electronic circuits,biomedicine,etc.ideas.The main work and research results of this paper are as follows:1.A wearable dipole wrist antenna based on liquid metal and a 3D printing tri-band liquid metal antenna for wrist-worn application is proposed in this article.Firstly,the structure of dipole antenna is proposed,which can cover with 2.4GHz,3.3GHz,5.5GHz by loading the branches.When the change of the branch length is ±0.5mm,the error sensitivity of the antenna does not exceed 4%.This antenna is fabricated out first by 3D printing the substrate with hollow channels conformal to the human wrist,and then filling the channels with liquid metal as the antenna radiating conductor.The combination of 3D printing and liquid metal can quickly fabricate wearable antennas with flexible structures.2.A wearable PIFA antenna based on liquid metal fabricated by a combination of flexible material PDMS and liquid metal EGa In is proposed in this article.Firstly,the PIFA antenna structure is proposed,which can cover with 2.4GHz and 5.8GHz dual-band communication by opening a U-shaped slot in the radiation element.The designed wearable antenna processing includes the layer-bonding method to prepare PDMS wristband structure and the vacuum compression method to inject liquid metal.When making PDMS wristband,the PIFA antenna is divided into three layers,and the base model is made by soft lithography respectively and then processed.The microfluidic channel is formed by bonding.When injecting the liquid metal,the EGa In and the wristband are placed in a vacuum box at the same time,and the EGa In is pressed into the microfluidic channel by the atmospheric pressure.Wearable antennas combined with flexible materials and liquid metals can be bent arbitrarily and meet different application scenarios. |
