Liquid-Metal-Filled 3-D Antenna Array Structure With an Integrated Feeding Network

• Published in: IEEE antennas and wireless propagation letters 2018-05, Vol.17 (5), p.739-742
• Main Authors: Bharambe, Vivek, Parekh, Dishit P., Ladd, Collin, Moussa, Khalil, Dickey, Michael D., Adams, Jacob J.
• Format: Article
• Language: English
• Subjects: 3-D printing; array antenna; Cavity resonators; coaxial feed network; Conductors; Feeds; liquid metal; Metals; Microstrip; Microstrip antenna arrays; Three-dimensional displays; vacuum filling
• ISSN: 1536-1225; 1548-5757
• DOI: 10.1109/LAWP.2018.2813309

This letter describes the fabrication and characterization of a microstrip patch array and a three-dimensional (3-D) coaxial feed network embedded within a 3-D printed part. Internal cavities within the acrylic structure are filled with a gallium-based liquid metal alloy using a vacuum-driven process to form conducting elements. In this way, four rectangular patch elements and a feeding network, including power dividers and vertical transitions, are embedded within a single 3-D printed acrylic geometry. Simulations and measurements of a 6 GHz array show that the array produces a matched response and moderate gain at the design frequency. This procedure can be employed to integrate numerous radiating elements and their corresponding feeding networks into a single monolithic acrylic structure, eliminating the need for separate fabrication of printed-circuit-board-based antennas and feeds. The procedure can serve as a convenient approach for rapid prototyping of complex array designs that exploit the additional spatial degrees of freedom to enhance their electromagnetic performance. Furthermore, manipulating the liquid-phase metallization inside these acrylic cavities can potentially be used to produce frequency- or pattern-reconfigurable arrays in the future.