RF Connectors for Origami Antennas

Undergraduate #465
Discipline: Technology and Engineering
Subcategory: Electrical Engineering
Session: 1
Room: Exhibit Hall A

Ricardo Sendrea - Florida International University
Co-Author(s): Gian Carrara, Florida International University, FL; Nicholas Russo, Florida International University, FL; Constantinos Zekios, Florida International University, FL; Stavros Georgakopoulos, Florida International University, FL

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Reconfigurable antennas provide novel capabilities to wireless communication systems that can support multiple wireless services. Numerous reconfigurable techniques have been proposed including electrical and mechanical reconfigurations [1], [2]. In this work, origami antennas are explored as they provide multifunctionality and efficient stowage, [2]. The development of origami antennas faces several challenges, such as the following: i) the fatigue of the substrate materials as these antennas fold/unflod, ii) the durability of the conductive material across hinges and folding creases, iii) the transition between different conductive materials used by origami antennas and iv) RF connectors for foldable designs. This research focuses on addressing the last challenge by investigating different RF connectors for origami antennas. Conductive materials can be generally characterized as rigid or flexible. When flexible materials are used (e.g., inks, fabrics, and threads that are conductive) a reliable connection between them and standard rigid RF connectors cannot be easily maintained and standard soldering techniques are not reliable. Consequently, alternative permanent connection techniques are explored, such as conductive epoxy and low-temperature soldering. Equally important to the reliability of the connection is the fabrication cost. Previous work presented in the literature has focused on the following: providing economic, detachable connection through the use of metal button snaps, [3], conductive Velcro, [4], and various embroidery techniques, [5]. In this work, first conductive Velcro is evaluated. The conductive Velcro is used along with conductive epoxy to connect two rigid microstrip lines. Our results show that this connection works properly and maintains an insertion loss of less than 0.5 dB up to 3 GHz. Also, a second RF connection technique, which uses snap buttons, is introduced. We investigate this second technique to increase the frequency range, where the insertion loss is less than 0.5 dB. The outcomes of this research are expected to contribute to the development of origami antennas as well flexible and wearable wireless systems. References: [1] C. G. Christodoulou, et al., “Reconfigurable Antennas for Wireless and Space Applications,” in Proceedings of the IEEE, vol. 100, no. 7, pp. 2250-2261, July 2012. [2] X. Liu, et al., “Analysis of a Packable and Tunable Origami Multi-Radii Helical Antenna,” in IEEE Access, vol. 7, pp. 13003-13014, 2019. [3] T. Kellomaki, “Snap-on buttons in a coaxial-to-microstrip transition,” 2009 Loughborough Antennas & Propagation Conference, 2009. [4] R. Seager, et al., “Flexible radio frequency connectors for textile electronics,” Electronics Letters, vol. 49, no. 22, pp. 1371–1373, 2013. [5] D.M.S. Fonseca, “Embroidered textile connectors for wearable systems,” Ph.D dissertation, Loughborough Uni., London, 2019.

Funder Acknowledgement(s): This work was supported by the National Science Foundation under grant EFRI 1332348 (which includes a REM grant), the Air Force Office of Scientific Research under grant FA9550-18-1-0191 and the Florida International University Presidential Fellowship.

Faculty Advisor: Stavros Georgakopoulos, georgako@fiu.edu

Role: I worked on testing and developing origami feeding techniques.