Low-Cost 3D-Printed Coupling-Fed Frequency Agile Fluidic Monopole Antenna System

A low-cost 3D-printed frequency agile fluidic monopole antenna system is demonstrated to respond to the increasing demand for reconfigurable antennas, which can operate in a dynamic environment, in this paper. Antennas that can be reconfigured for different operating frequencies, polarizations, or radiation patterns are attracting attention. Traditional reconfigurable antennas using a metallic radiating element with electronic switches are limited by their pre-defined physical geometries. As conductive fluid, either liquid metal or ionized fluid has no defined shape, so it is possible to create the desired shape of a fluidic antenna to support different wireless environments. The fabrication of the leakage-free containers for fluidic antennas needs special consideration, and stereo-lithography-based 3D-printing technology is a possible option to support the fabrication. Moreover, researchers will have higher design freedom and accuracy to create new container shapes for fluidic antennas. The fluidic monopole antenna proposed is coupling-fed by a ring geometry for separating the electrical and mechanical structures; such an approach enables individual optimization and minimizes mutual disturbances in the system. A parametric study of the proposed coupling-feed geometry and the experimental verification of the antenna prototypes have been performed. Reasonable frequency agility from 3.2 to 5 GHz has been demonstrated, and the peak efficiency is about 80%. A maximum gain of 3.8 dBi is obtained. The radiation patterns of the antenna are stable across the operating bandwidth. The proposed antenna could be useful for the applications in the recent 5G mid-bands operations.