{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,28]],"date-time":"2026-03-28T17:15:22Z","timestamp":1774718122024,"version":"3.50.1"},"reference-count":49,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2018,10,16]],"date-time":"2018-10-16T00:00:00Z","timestamp":1539648000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Chalmers Foundation Excellence Grant","award":["None"],"award-info":[{"award-number":["None"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We have developed a transmission-based, open-ended coaxial dielectric probe that can be used in clinical situations and overcomes many of the limitations related to the typical reflection-based dielectric probes. The approach utilizes the low profile, open-ended coaxial cables enabling clinicians to still probe relatively compact spaces. The sensing depth can be extended to as large as 1.5 to 2 cm compared with the more typical range of 0.3 mm for conventional probes and is dramatically less affected by measurement technique variability including poor sample contact and cable bending. As a precursor to an actual clinical implementation, we study the technique in a range of homogeneous liquids with substantially varying dielectric properties. The initial results demonstrate good agreement between the transmission-based probe and commercial, reflection-based probes and pave the way for more substantial clinical implementation.<\/jats:p>","DOI":"10.3390\/s18103484","type":"journal-article","created":{"date-parts":[[2018,10,16]],"date-time":"2018-10-16T11:07:51Z","timestamp":1539688071000},"page":"3484","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":17,"title":["A Transmission-Based Dielectric Property Probe for Clinical Applications"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3852-5203","authenticated-orcid":false,"given":"Paul","family":"Meaney","sequence":"first","affiliation":[{"name":"Electrical Engineering Department, Chalmers University of Technology, 41296 Gothenburg, Sweden"},{"name":"Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2415-0743","authenticated-orcid":false,"given":"Tomas","family":"Rydholm","sequence":"additional","affiliation":[{"name":"Electrical Engineering Department, Chalmers University of Technology, 41296 Gothenburg, Sweden"}]},{"given":"Helena","family":"Brisby","sequence":"additional","affiliation":[{"name":"Sahlgrenska University Hospital, 41345 Gothenburg, Sweden"}]}],"member":"1968","published-online":{"date-parts":[[2018,10,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"82","DOI":"10.1109\/TMTT.1982.1131021","article-title":"Measurement of radio frequency permittivity of biological tissue with an open-ended coaxial line: Part 1","volume":"30","author":"Athey","year":"1982","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1109\/10.1374","article-title":"Dielectric properties of breast carcinoma and the surrounding tissues","volume":"35","author":"Surowiec","year":"1988","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2251","DOI":"10.1088\/0031-9155\/41\/11\/002","article-title":"The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz","volume":"41","author":"Gabriel","year":"1996","journal-title":"Phys. Med. Biol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1118\/1.597312","article-title":"The measured electrical properties of normal and malignant human tissue from 50 to 900 MHz","volume":"41","author":"Joines","year":"1994","journal-title":"Med. Phys."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"2637","DOI":"10.1088\/0031-9155\/52\/10\/001","article-title":"A large-scale study of the ultrawideband microwave dielectric properties of normal breast tissue obtained from reduction surgeries","volume":"52","author":"Lazebnik","year":"2007","journal-title":"Phys. Med. Biol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"045001","DOI":"10.1088\/2057-1976\/aa74c4","article-title":"Investigation on the effect of hydration on tissue dielectric properties in the ex vivo measurements","volume":"3","author":"Shahzad","year":"2017","journal-title":"Biomed. Phys. Eng. Express"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Greene, A.K. (2015). Assessing free and bound water in skin at 300 MHz using tissue dielectric constant measurements with the MoistureMeterD. Lymphedema. Presentation, Diagnosis, and Treatment, Springer International Publishing.","DOI":"10.1007\/978-3-319-14493-1"},{"key":"ref_8","unstructured":"Hodgetts, T.E. (1981). The Calculation of the Equivalent Circuits of Coaxial-Line Step Discontinuities, Royal Signals and Radar Establishment. Memorandum No. 3422."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Blackham, D., and Pollard, R. (1993, January 14\u201318). Finite element analysis of open-ended coaxial lines. Proceedings of the 1993 IEEE MTT-S International Microwave Symposium Digest, Atlanta, GA, USA.","DOI":"10.1109\/MWSYM.1993.277099"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"757","DOI":"10.1088\/0022-3735\/22\/9\/015","article-title":"A critical study of the open-ended coaxial line sensor technique for RF and microwave complex permittivity measurements","volume":"22","author":"Grant","year":"1989","journal-title":"J. Phys. E Sci. Instrum."},{"key":"ref_11","unstructured":"Chan, T.Y.A., Gabriel, C., and Grant, E.H. (1992, January 7\u201310). Modeling of the reflection coefficient of an open ended coaxial line and its use for accurate complex permittivity measurements at frequencies up to 20 GHz. Proceedings of the Sixth International Conference on Dielectric Materials, Measurements and Applications, Manchester, UK."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1109\/TIM.1980.4314902","article-title":"Coaxial line reflection method for measuring dielectric properties of biological substances at radio and microwave frequencies\u2014A review","volume":"29","author":"Stuchly","year":"1980","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1109\/TMTT.1983.1131507","article-title":"Numerical analysis of open-ended coaxial lines","volume":"31","author":"Gajda","year":"1983","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"S121","DOI":"10.1088\/0967-3334\/30\/6\/S08","article-title":"The correlation of in vivo and ex vivo tissue dielectric properties to validate electromagnetic breast imaging: Initial clinical experience","volume":"30","author":"Halter","year":"2009","journal-title":"Physiol. Meas."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1007\/BF02347692","article-title":"Changes in electrical resistivity of swine liver after occlusion and postmortem","volume":"40","author":"Haemmerich","year":"2002","journal-title":"Med. Biol. Eng. Comput."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"51","DOI":"10.1111\/j.1749-6632.1999.tb09448.x","article-title":"In vivo and in situ ischemic tissue characterization using electrical impedance spectroscopy","volume":"873","author":"Casas","year":"1999","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_17","unstructured":"Keysight Technologies (2003). Technical Overview, Agilent 85070E Dielectric Probe Kit 200 MHz to 50 GHz, Agilent Technologies. Agilent Literature Number 5988-9472EN."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1241","DOI":"10.1109\/10.720202","article-title":"Variational formulation of open-ended coaxial line in contact with layered biological medium","volume":"45","author":"Alanen","year":"1998","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_19","unstructured":"Delfin Technologies (2018, May 25). Delfin Technologies Ltd.: Kuopio, Finland. Available online: http:\/\/www.delfintech.com\/en\/product_information\/moisturemeterd\/."},{"key":"ref_20","unstructured":"SPEAG (2018, May 10). Schmid and Partner Engineering AG: Zurich, Switzerland. Available online: https:\/\/www.speag.com\/products\/dak\/dielectric-measurements\/."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Meaney, P.M., Gregory, A., Epstein, N.R., and Paulsen, K.D. (2014). Microwave open-ended coaxial dielectric probe: Interpretation of the sensing volume re-visited. BMC Med. Phys., 14.","DOI":"10.1186\/1756-6649-14-3"},{"key":"ref_22","first-page":"915","article-title":"Open-ended coaxial dielectric probe effective penetration depth determination","volume":"64","author":"Meaney","year":"2016","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_23","unstructured":"Gregory, A.P., Clarke, R.N., Hodgetts, T.E., and Symm, G.T. (2008). RF and Dielectric Measurements Upon Layered Materials Using Coaxial Sensors, National Physical Laboratory. Report MAT 13."},{"key":"ref_24","unstructured":"Emerson, J.A., and Torkelson, J.M. (1991). The methods of investigation of complex dielectric permittivity of layer polymers containing conductive inclusion. Optical and Electrical Properties of Polymers, Materials Research Society Symposia Proceedings, Materials Research Society."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"88","DOI":"10.7716\/aem.v6i3.428","article-title":"Microwave interferometry based on open-ended coaxial technique for high sensitivity liquid testing","volume":"6","author":"Bakli","year":"2017","journal-title":"Adv. Electromagn."},{"key":"ref_26","unstructured":"Haddadi, K., Bakli, H., and Lasri, T. (December, January 30). Wide-band near-field microwave microscope operating in transmission mode. Proceedings of the 5th International Conference on Electromagnetic Near-Field Characterization and Imaging, Rouen, France."},{"key":"ref_27","unstructured":"Harris, N.H., Chow, J.R., Eisenhart, R.L., and Pierce, B.M. (May, January 29). Dielectric properties of ceramics at microwave frequencies. Proceedings of the Symposium on Microwave Theory and Application in Materials Processing, Annual Meeting of the American Ceramic Society, Cincinnati, OH, USA."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1109\/TIM.1970.4313932","article-title":"Measurement of the intrinsic properties of materials by time-domain techniques","volume":"19","author":"Nicolson","year":"1970","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1109\/PROC.1974.9382","article-title":"Automatic measurement of complex dielectric constant and permeability at microwave frequencies","volume":"62","author":"Weir","year":"1974","journal-title":"Proc. IEEE"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2872","DOI":"10.1109\/TIM.2011.2122150","article-title":"Waveguide measurements of the permittivity and permeability at temperatures of up to 1000 \u00b0C","volume":"60","author":"Larsson","year":"2011","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1088\/0957-0233\/14\/5\/308","article-title":"Free-space measurement of dielectric properties of cereal grain and oilseed at microwave frequencies","volume":"14","author":"Trabelsi","year":"2003","journal-title":"Meas. Sci. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1109\/19.52520","article-title":"Free-space measurement of complex permittivity and complex permeability of magnetic materials at microwave frequencies","volume":"39","author":"Ghodgaonkar","year":"1990","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_33","unstructured":"Amiet, A., and Jewsbury, P. (2000, January 3\u20136). Free space microwave permittivity and permeability measurements. Proceedings of the 2000 Asia-Pacific Microwave Conferenc, Sydney, Australia."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1199","DOI":"10.3390\/s150101199","article-title":"Average dielectric properties analysis of complex breast tissue with microwave transmission measurements","volume":"15","author":"Garrett","year":"2015","journal-title":"Sensors"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"7387","DOI":"10.2528\/PIER16122204","article-title":"Antenna Calibration Method for Dielectric Property Estimation of Biological Tissues at Microwave Frequencies","volume":"158","author":"Garrett","year":"2017","journal-title":"Prog. Electromagn. Res."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1118\/1.594766","article-title":"Microwave time delay spectroscopic imagery of isolated canine kidney","volume":"7","author":"Jacobi","year":"1980","journal-title":"Med. Phys."},{"key":"ref_37","first-page":"573217","article-title":"High resolution software defined radar system for target detection","volume":"2013","author":"Costanzo","year":"2013","journal-title":"J. Electr. Comput. Eng."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1016\/S0140-6736(15)60692-4","article-title":"Global, regional, and national prevalence, and years lived with disability for 310 diseases and injuries, 1990\u20132013: A systemic analysis for the Global Burden of Disease Study 2013","volume":"386","author":"Vos","year":"2015","journal-title":"Lancet"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"253","DOI":"10.5435\/JAAOS-D-14-00042","article-title":"Management of osteoporosis in spine surgery","volume":"23","author":"Lehman","year":"2015","journal-title":"J. Am. Acad. Orthop. Surg."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"S81","DOI":"10.1007\/s00198-003-1478-0","article-title":"Measuring the structural strength of bones with dual-energy X-ray absorptiometry: Principles, technical limitations, and future possibilities","volume":"14","author":"Beck","year":"2003","journal-title":"Osteoporos. Int."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"667","DOI":"10.1038\/ncprheum0928","article-title":"Common mistakes in the clinical use of bone mineral density testing","volume":"4","author":"Lewiecki","year":"2008","journal-title":"Nat. Clin. Pract. Rheumatol."},{"key":"ref_42","unstructured":"Herkowitz, H.N., Dvorak, J., Bell, G.R., Nordin, M., and Grob, D. (2004). The Lumbar Spine, Lippincott Williams & Wilkins."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1177\/2151458513500787","article-title":"Failure of cement-augmented pedicle screws in the osteoporotic spine: A case report","volume":"4","author":"Mesfin","year":"2013","journal-title":"Geriatr. Orthop. Surg. Rehabil."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/j.spinee.2010.09.024","article-title":"Instrumentation of the osteoporotic spine: Biomechanical and clinical consideration","volume":"11","author":"Ponnusamy","year":"2011","journal-title":"Spine J."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"697253","DOI":"10.1155\/2012\/697253","article-title":"Surface wave multi-path signals in near-field microwave imaging","volume":"2012","author":"Meaney","year":"2012","journal-title":"Int. J. Biomed. Imaging"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"103101","DOI":"10.1118\/1.4820361","article-title":"Integration of a microwave tomographic imaging system with MR for improved breast imaging","volume":"40","author":"Meaney","year":"2013","journal-title":"Med. Phys."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4239","DOI":"10.1002\/mp.12384","article-title":"Two-step inversion in microwave imaging with a logarithmic transformation","volume":"44","author":"Meaney","year":"2017","journal-title":"Med. Phys."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"N413","DOI":"10.1088\/0031-9155\/55\/15\/N02","article-title":"Cole-Cole parameters for the dielectric properties of porcine tissues as a function of age at microwave frequencies","volume":"55","author":"Peyman","year":"2010","journal-title":"Phys. Med. Biol."},{"key":"ref_49","unstructured":"Meaney, P.M., Bulumulla, S., Hartov, A., Raynolds, T., Miller, A., Richter, S., and Schoenberger, F. (2018). Low cost, high performance, 16-channel microwave measurement system for tomographic applications. Rev. Sci. Instrum, in press."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/10\/3484\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:26:02Z","timestamp":1760196362000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/10\/3484"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,10,16]]},"references-count":49,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2018,10]]}},"alternative-id":["s18103484"],"URL":"https:\/\/doi.org\/10.3390\/s18103484","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,10,16]]}}}