{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:50:57Z","timestamp":1760233857212,"version":"build-2065373602"},"reference-count":42,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2021,3,4]],"date-time":"2021-03-04T00:00:00Z","timestamp":1614816000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This work presents the design and fabrication of two multi-element structurally embedded vascular antennas (SEVAs). These are achieved through advances in additively manufactured sacrificial materials and demonstrate the ability to embed vascular microchannels in both planar and complex-curved epoxy-filled quartz fiber structural composite panels. Frequency-reconfigurable antennas are formed by these structures through the pressure-driven transport of liquid metal through the embedded microchannels. The planar multi-layer topology examines the ability to fabricate two co-located radiating structures separated by a single ply of quartz fabric within the composite layup. The multi-element linear array topology composed of microchannels embedded on to a single-layer are used to demonstrate the ability to conformally-integrate these channels into a complex curved surface that mimics an array of antennas on the leading edge of an Unmanned Aerial Vehicle (UAV). A parallel-strip antipodal dipole feed structure provides excitation and serves as the interface for fluid displacement within the microchannels to facilitate reconfiguration. The nominal design of the SEVAs achieve over a decade of frequency reconfiguration with respect to the fundamental dipole mode of the antenna. Experimental and predicted results demonstrate the operation for canonical states of the antennas. Additional results for the array topology demonstrate beam steering and contiguous operation of interconnected elements in the multi-element structure.<\/jats:p>","DOI":"10.3390\/s21051764","type":"journal-article","created":{"date-parts":[[2021,3,5]],"date-time":"2021-03-05T00:39:07Z","timestamp":1614904747000},"page":"1764","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Multi-Layer and Conformally Integrated Structurally Embedded Vascular Antenna (SEVA) Arrays"],"prefix":"10.3390","volume":"21","author":[{"given":"Amrita","family":"Bal","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas A&amp;M University, College Station, TX 77843, USA"}]},{"given":"Jeffery W.","family":"Baur","sequence":"additional","affiliation":[{"name":"Materials and Manufacturing Directorate, U.S. Air Force Research Laboratory, WBAFB, Dayton, OH 45433, USA"}]},{"given":"Darren J.","family":"Hartl","sequence":"additional","affiliation":[{"name":"Department of Aerospace Engineering, Texas A&amp;M University, College Station, TX 77843, USA"},{"name":"Department of Material Science and Engineering, Texas A&amp;M University, College Station, TX 77840, USA"}]},{"given":"Geoffrey J.","family":"Frank","sequence":"additional","affiliation":[{"name":"Materials and Manufacturing Directorate, U.S. Air Force Research Laboratory, WBAFB, Dayton, OH 45433, USA"},{"name":"University of Dayton Research Institute, 300 College Park, Dayton, OH 45469, USA"}]},{"given":"Thao","family":"Gibson","sequence":"additional","affiliation":[{"name":"University of Dayton Research Institute, 300 College Park, Dayton, OH 45469, USA"}]},{"given":"Hong","family":"Pan","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Texas A&amp;M University, College Station, TX 77843, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7226-1723","authenticated-orcid":false,"given":"Gregory H.","family":"Huff","sequence":"additional","affiliation":[{"name":"Department of Electrical Engineering, Pennsylvania State University, State College, PA 16801, USA"}]}],"member":"1968","published-online":{"date-parts":[[2021,3,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Inata, H., Say, S., Ando, T., Liu, J., and Shimamoto, S. (2016, January 3\u20136). Unmanned aerial vehicle based missing people detection system employing phased array antenna. Proceedings of the 2016 IEEE Wireless Communications and Networking Conference, Doha, Qatar.","DOI":"10.1109\/WCNC.2016.7564674"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1109\/MCOM.2018.1700991","article-title":"On the Use of Unmanned Aerial Vehicles for Antenna and Coverage Diagnostics in Mobile Networks","volume":"56","author":"Fernandez","year":"2018","journal-title":"IEEE Commun. Mag."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1007\/s10846-017-0548-z","article-title":"Drone-Aided Healthcare Services for Patients with Chronic Diseases in Rural Areas","volume":"88","author":"Kim","year":"2017","journal-title":"J. Intell. Robot. Syst."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"6968","DOI":"10.1109\/TAP.2017.2766439","article-title":"Wideband and Multipolarization Reconfigurable Crossed Bowtie Dipole Antenna","volume":"65","author":"Tran","year":"2017","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Yoon, S., Tak, J., Choi, J., and Park, Y.-M. (2017, January 9\u201314). Conformal monopolar antenna for UAV applications. Proceedings of the IEEE International Symposium on Antennas and Propagation & USNC\/URSI National Radio Science Meeting, San Diego, CA, USA.","DOI":"10.1109\/APUSNCURSINRSM.2017.8072301"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"3857","DOI":"10.1109\/TAP.2018.2835524","article-title":"Broadband Slotted Blade Dipole Antenna for Airborne UAV Applications","volume":"66","author":"Nosrati","year":"2018","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"2919","DOI":"10.1109\/LAWP.2017.2752358","article-title":"Compact and Low-Profile Omnidirectional Circularly Polarized Antenna with Four Coupling Arcs for UAV Applications","volume":"16","author":"Wu","year":"2017","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"6130","DOI":"10.1109\/ACCESS.2017.2766231","article-title":"A Wideband Quad-Polarization Reconfigurable Metasurface Antenna","volume":"6","author":"Hu","year":"2018","journal-title":"IEEE Access"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"127486","DOI":"10.1109\/ACCESS.2019.2939511","article-title":"Low-Profile Conformal UWB Antenna for UAV Applications","volume":"7","author":"Balderas","year":"2019","journal-title":"IEEE Access"},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Seo, D.-G., Jeong, C.-H., Choi, Y.-S., Park, J.-S., Jeong, Y.-Y., and Lee, W.-S. (2019, January 7\u201312). Wide Beam Coverage Dipole Antenna Array with Parasitic Elements for UAV Communication. Proceedings of the IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, Atlanta, GA, USA.","DOI":"10.1109\/APUSNCURSINRSM.2019.8888747"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Costa, A., Goncalves, R., Pinho, P., and Carvalho, N.B. (2017, January 9\u201314). Design of UAV and ground station antennas for communications link budget improvement. Proceedings of the IEEE International Symposium on Antennas and Propagation & USNC\/URSI National Radio Science Meeting, San Diego, CA, USA.","DOI":"10.1109\/APUSNCURSINRSM.2017.8073356"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Lee, C.U., Noh, G., Ahn, B., Yu, J.-W., and Lee, H.L. (2019). Tilted-Beam Switched Array Antenna for UAV Mounted Radar Applications with 360\u00b0 Coverage. Electronics, 8.","DOI":"10.3390\/electronics8111240"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2169","DOI":"10.1109\/TAP.2010.2048852","article-title":"Polymer-Carbon Nanotube Sheets for Conformal Load Bearing Antennas","volume":"58","author":"Zhou","year":"2010","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2451","DOI":"10.1109\/TAP.2010.2048862","article-title":"Reinforced Continuous Carbon-Fiber Composites Using Multi-Wall Carbon Nanotubes for Wideband Antenna Applications","volume":"58","author":"Mehdipour","year":"2010","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Biswas, S. (2018, January 8\u201313). Fabrication of Conformal Load Bearing Antenna using 3D Printing. Proceedings of the IEEE International Symposium on Antennas and Propagation & USNC\/URSI National Radio Science Meeting, Boston, MA, USA.","DOI":"10.1109\/APUSNCURSINRSM.2018.8608257"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Chen, C., and Zheng, H. (2017, January 16\u201319). Design of a dual-band conformai antenna on a cone surface for missle-borne. Proceedings of the Sixth Asia-Pacific Conference on Antennas and Propagation (APCAP), Xi\u2019an, China.","DOI":"10.1109\/APCAP.2017.8420994"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"631","DOI":"10.1177\/1045389X13493358","article-title":"Structural design and development of multiband aero-vehicle smart skin antenna","volume":"25","author":"Kim","year":"2014","journal-title":"J. Intell. Mater. Syst. Struct."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"331","DOI":"10.1016\/j.compositesb.2015.03.091","article-title":"Cylindrical conformal single-patch microstrip antennas based on three dimensional woven glass fiber\/epoxy resin composites","volume":"78","author":"Xu","year":"2015","journal-title":"Compos. Part B Eng."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Liu, Y., Du, H., Liu, L., and Leng, J. (2014). Shape memory polymers and their composites in aerospace applications: A review. Smart Mater. Struct., 23.","DOI":"10.1088\/0964-1726\/23\/2\/023001"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"2359","DOI":"10.1109\/TAP.2015.2409866","article-title":"A Broadband High-Gain Bi-Layer LPDA for UHF Conformal Load-Bearing Antenna Structures (CLASs) Applications","volume":"63","author":"Bishop","year":"2015","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Bishop, N., Ali, M., Baron, W., Miller, J., Tuss, J., Zeppettella, D., and Ali, M. (2014, January 6\u201311). Aperture coupled MEMS reconfigurable pixel patch antenna for conformal load bearing antenna structures (CLAS). Proceedings of the 2014 IEEE Antennas and Propagation Society International Symposium (APSURSI), Memphis, TN, USA.","DOI":"10.1109\/APS.2014.6904872"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1381","DOI":"10.1109\/LAWP.2014.2339636","article-title":"Stretchable and Flexible E-Fiber Wire Antennas Embedded in Polymer","volume":"13","author":"Kiourti","year":"2014","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"885","DOI":"10.1016\/j.compositesb.2011.01.006","article-title":"Fabrication and characterization of microstrip array antennas integrated in the three dimensional orthogonal woven composite","volume":"42","author":"Yao","year":"2011","journal-title":"Compos. Part B Eng."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"230","DOI":"10.1109\/LAWP.2016.2570807","article-title":"Conformal Load-Bearing Spiral Antenna on Conductive Textile Threads","volume":"16","author":"Zhong","year":"2016","journal-title":"IEEE Antennas Wirel. Propag. Lett."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"4141","DOI":"10.1109\/TAP.2012.2207055","article-title":"Embroidered Conductive Fibers on Polymer Composite for Conformal Antennas","volume":"60","author":"Wang","year":"2012","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_26","unstructured":"Du, C.-Z., Zhong, S.-S., Yao, L., and Qiu, Y.-P. (2010, January 17\u201320). Textile microstrip two-element array antenna on 3D orthogonal woven composite. Proceedings of the 2010 International Symposium on Signals, Systems and Electronics, Nanjing, China."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Ghorbani, K. (2014, January 4\u20136). Conformal load bearing antenna structure using Carbon Fibre Reinforced Polymer (CFRP). Proceedings of the International Workshop on Antenna Technology: Small Antennas, Novel EM Structures and Materials, and Applications (iWAT), Sydney, Australia.","DOI":"10.1109\/IWAT.2014.6958612"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Kim, M.-S., Park, C.-Y., Cho, C.-M., and Jun, S.-M. (2014, January 6\u201311). A multi-band smart skin antenna design for flight demonstration. Proceedings of the 8th European Conference on Antennas and Propagation (EuCAP 2014), The Hague, The Netherlands.","DOI":"10.1109\/EuCAP.2014.6902422"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1049\/el.2013.2971","article-title":"Two-octave tunable liquid-metal monopole antenna","volume":"50","author":"Morishita","year":"2014","journal-title":"Electron. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2282","DOI":"10.1109\/TAP.2017.2679075","article-title":"A Physically Reconfigurable Structurally Embedded Vascular Antenna","volume":"65","author":"Huff","year":"2017","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"091905","DOI":"10.1063\/1.4961910","article-title":"Liquid gallium and the eutectic gallium indium (EGaIn) alloy: Dielectric functions from 1.24 to 3.1 eV by electrochemical reduction of surface oxides","volume":"109","author":"Morales","year":"2016","journal-title":"Appl. Phys. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1016\/j.compstruct.2016.01.106","article-title":"Effects of microchannels on the mechanical performance of multifunctional composite laminates with unidirectional laminae","volume":"143","author":"Hartl","year":"2016","journal-title":"Compos. Struct."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"025002","DOI":"10.1088\/1361-665X\/aa513d","article-title":"A liquid metal-based structurally embedded vascular antenna: II. Multiobjective and parameterized design exploration","volume":"26","author":"Hartl","year":"2016","journal-title":"Smart Mater. Struct."},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Hartl, D.J., Huff, G.H., Pan, H., Smith, L., Bradford, R.L., Frank, G.J., and Baur, J.W. (2016, January 20). Analysis and characterization of structurally embedded vascular antennas using liquid metals. Proceedings of the Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, Las Vegas, NV, USA.","DOI":"10.1117\/12.2219258"},{"key":"ref_35","first-page":"1","article-title":"A liquid metal-based structurally embedded vascular antenna: I. Concept and Multiphysics Modelling","volume":"26","author":"Hartl","year":"2017","journal-title":"Smart Mater. Struct."},{"key":"ref_36","unstructured":"(2021, January 27). Ansys HFSS: High Frequency Structural Simulator. Available online: https:\/\/www.ansys.com\/products\/electronics\/ansys-hfss."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Stein, F.M. (1980). The Curve Parallel to a Parabola Is Not a Parabola: Parallel Curves, Taylor & Francis, Ltd.","DOI":"10.2307\/3027202"},{"key":"ref_38","unstructured":"(2021, January 27). 3MTM FluorinertTM Electronic Liquid FC-70\u20133M Science Applied to Life. Available online: https:\/\/multimedia.3m.com\/mws\/media\/64891O\/fluorinert-electronic-liquid-fc-70.pdf."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"2263","DOI":"10.1109\/TAP.2016.2551259","article-title":"Simple Formula for Aperture Efficiency Reduction Due to Grating Lobes in Planar Phased Arrays","volume":"64","author":"Vosoogh","year":"2016","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"7320","DOI":"10.1109\/TAP.2020.2998219","article-title":"Planar 2-D Beam Steering Antenna Using Liquid Metal Parasitics","volume":"68","author":"Bharambe","year":"2020","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"7630","DOI":"10.1109\/TAP.2020.2993110","article-title":"A Frequency- and Polarization-Reconfigurable Slot Antenna Using Liquid Metal","volume":"68","author":"Liu","year":"2020","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"856","DOI":"10.1109\/LAWP.2019.2903781","article-title":"A Multistate Frequency Reconfigurable Monopole Antenna Using Fluidic Channels","volume":"18","author":"Singh","year":"2019","journal-title":"IEEE Antennas Wirel. Propag. Lett."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/5\/1764\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T05:32:34Z","timestamp":1760160754000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/21\/5\/1764"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,4]]},"references-count":42,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2021,3]]}},"alternative-id":["s21051764"],"URL":"https:\/\/doi.org\/10.3390\/s21051764","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2021,3,4]]}}}