Reconfigurable Liquid Metal Antennas for Shape-Adaptive Communication Systems
DOI:
https://doi.org/10.64235/a0j99845Keywords:
Liquid metal antenna; EGaIn; Galinstan; reconfigurable antenna; microfluidic; frequency agility; bandwidth reconfiguration; polarization diversity; beam steering; PDMS; shape-adaptive; soft electronics; 5G; wearable antennaAbstract
The paper offers a comprehensive synthesis of the research on reconfigurable liquid metal (LM) antennas as enablers for shape-adaptive communication systems, in which the 20 peer-reviewed works published between 2008 and 2020 are summarized. Liquid metal alloys are analysed as excellent radiating conductors with electrical conductivities ranging from 3.4 to 6.7 × 10⁶ S/m, and with intrinsic fluidic reconfigurability, particularly those made up of eutectic gallium–indium (EGaIn) alloy and Galinstan. Its synthesis encompasses four main modalities of reconfiguration including: frequency, bandwidth, polarization, and beam-pattern adaptation that are enabled by the microfluidic actuation, the electrochemical control, the mechanical deformation, and the pressure-driven manipulation of the channel within the compliant substrates (e.g., polydimethylsiloxane (PDMS)). Some of the key quantitative results are: The demonstrated bandwidth tuning ratio is 9:1; frequency agility range is 0.5 GHz to 6 GHz; and radiation efficiency is more than 88% for optimized configuration. Fourteen representative prototype designs are presented and their performance compared, and a structured assessment of fabrication methods, such as soft lithography, direct ink writing, and 3D-printed microfluidics, is available. The synthesis pinpoints some persistent issues related to the actuation speed, oxide-layer control on EGaIn surfaces and hermetic sealing of LM channels. Looking forward, the integration of 5G millimeter-wave network platforms, wearable body area networks and satellite communication terminals is highlighted in line with the 2020 knowledge boundary. The results show that LM-based reconfigurable antennas have indeed a transformative technology trajectory with high potential for next-generation adaptive wireless systems.
References
J. J. Adams et al., “Conformal printing of electrically small antennas on three-dimensional surfaces,” Adv. Mater., vol. 23, no. 11, pp. 1335–1340, 2011.
K. Y. Alqurashi et al., “Liquid metal bandwidth-reconfigurable antenna,” IEEE Antennas Wireless Propag. Lett., vol. 19, no. 1, pp. 218–222, 2020.
Z. Chen, H. Wong, and J. Kelly, “A polarization-reconfigurable glass dielectric resonator antenna using liquid metal,” IEEE Trans. Antennas Propag., vol. 67, no. 5, pp. 3427–3432, 2019.
S. Cheng, Z. Wu, P. Hallbjörner, K. Hjort, and A. Rydberg, “Foldable and stretchable liquid metal planar inverted cone antenna,” IEEE Trans. Antennas Propag., vol. 57, no. 12, pp. 3765–3771, 2009.
C. G. Christodoulou, Y. Tawk, S. A. Lane, and S. R. Erwin, “Reconfigurable antennas for wireless and space applications,” Proc. IEEE, vol. 100, no. 7, pp. 2250–2261, 2012.
J. Costantine, Y. Tawk, S. E. Barbin, and C. G. Christodoulou, “Reconfigurable antennas: Design and applications,” Proc. IEEE, vol. 103, no. 3, pp. 424–437, 2015.
A. Dey, R. Guldiken, and G. Mumcu, “Microfluidically reconfigured wideband frequency-tunable liquid-metal monopole antenna,” IEEE Trans. Antennas Propag., vol. 64, no. 6, pp. 2572–2576, 2016.
M. D. Dickey, “Stretchable and soft electronics using liquid metals,” Adv. Mater., vol. 29, no. 27, Art. no. 1606425, 2017.
M. D. Dickey et al., “Eutectic gallium-indium (EGaIn): A liquid metal alloy for the formation of stable structures in microchannels at room temperature,” Adv. Funct. Mater., vol. 18, no. 7, pp. 1097–1104, 2008.
R. L. Haupt and M. Lanagan, “Reconfigurable antennas,” IEEE Antennas Propag. Mag., vol. 55, no. 1, pp. 49–61, 2013.
G. J. Hayes et al., “Flexible liquid metal alloy (EGaIn) microstrip patch antenna,” IEEE Trans. Antennas Propag., vol. 60, no. 5, pp. 2151–2156, 2012.
S. J. Mazlouman et al., “A reconfigurable patch antenna using liquid metal embedded in a silicone substrate,” IEEE Trans. Antennas Propag., vol. 59, no. 12, pp. 4406–4412, 2011.
A. M. Morishita, C. K. Y. Kitamura, A. T. Ohta, and W. A. Shiroma, “A liquid-metal monopole array with tunable frequency, gain, and beam steering,” IEEE Antennas Wireless Propag. Lett., vol. 12, pp. 1388–1391, 2013.
E. Motovilova and S. Y. Huang, “A review on reconfigurable liquid dielectric antennas,” Materials, vol. 13, no. 8, Art. no. 1863, 2020.
D. Rodrigo, L. Jofre, and B. A. Cetiner, “Circular beam-steering reconfigurable antenna with liquid metal parasitics,” IEEE Trans. Antennas Propag., vol. 60, no. 4, pp. 1796–1802, 2012.
A. P. Saghati et al., “Miniature and reconfigurable CPW folded slot antennas employing liquid-metal capacitive loading,” IEEE Trans. Antennas Propag., vol. 63, no. 9, pp. 3798–3807, 2015.
S. I. H. Shah and S. Lim, “Microfluidically frequency-reconfigurable quasi-Yagi dipole antenna,” Sensors, vol. 18, no. 9, Art. no. 2935, 2018.
J.-H. So et al., “Reversibly deformable and mechanically tunable fluidic antennas,” Adv. Funct. Mater., vol. 19, no. 22, pp. 3632–3637, 2009.
L. Song et al., “Wideband frequency reconfigurable patch antenna with switchable slots based on liquid metal and 3-D printed microfluidics,” IEEE Trans. Antennas Propag., vol. 67, no. 5, pp. 2886–2895, 2019.
M. Wang et al., “A reconfigurable liquid metal antenna driven by electrochemically controlled capillarity,” J. Appl. Phys., vol. 117, no. 19, Art. no. 194901, 2015.
Downloads
Published
Issue
Section
License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
