{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T03:09:45Z","timestamp":1771038585152,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2023,4,13]],"date-time":"2023-04-13T00:00:00Z","timestamp":1681344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Harbin Institute of Technology","award":["AUGA5710012022"],"award-info":[{"award-number":["AUGA5710012022"]}]},{"name":"Harbin Institute of Technology","award":["51977044"],"award-info":[{"award-number":["51977044"]}]},{"name":"National Natural Science Foundation of China","award":["AUGA5710012022"],"award-info":[{"award-number":["AUGA5710012022"]}]},{"name":"National Natural Science Foundation of China","award":["51977044"],"award-info":[{"award-number":["51977044"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The main disadvantage of the electromagnetic acoustic transducer (EMAT) is low energy-conversion efficiency and low signal-to-noise ratio (SNR). This problem can be improved by pulse compression technology in the time domain. In this paper, a new coil structure with unequal spacing was proposed for a Rayleigh wave EMAT (RW-EMAT) to replace the conventional meander line coil with equal spacing, which allows the signal to be compressed in the spatial domain. Linear and nonlinear wavelength modulations were analyzed to design the unequal spacing coil. Based on this, the performance of the new coil structure was analyzed by the autocorrelation function. Finite element simulation and experiments proved the feasibility of the spatial pulse compression coil. The experimental results show that the received signal amplitude is increased by 2.3~2.6 times, the signal with a width of 20 \u03bcs could be compressed into a \u03b4-like pulse of less than 0.25 \u03bcs and the SNR is increased by 7.1\u201310.1 dB. These indicate that the proposed new RW-EMAT can effectively enhance the strength, time resolution and SNR of the received signal.<\/jats:p>","DOI":"10.3390\/s23083943","type":"journal-article","created":{"date-parts":[[2023,4,13]],"date-time":"2023-04-13T02:09:21Z","timestamp":1681351761000},"page":"3943","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":20,"title":["A New Design to Rayleigh Wave EMAT Based on Spatial Pulse Compression"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-8326-860X","authenticated-orcid":false,"given":"Chuanliu","family":"Jiang","sequence":"first","affiliation":[{"name":"School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8218-0540","authenticated-orcid":false,"given":"Zhichao","family":"Li","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China"}]},{"given":"Zeyang","family":"Zhang","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China"}]},{"given":"Shujuan","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"832","DOI":"10.1109\/TUFFC.2019.2956711","article-title":"New Combination of Magnet and Coil of Electromagnetic Acoustic Transducer for Generating and Detecting Rayleigh Wave","volume":"67","author":"Sun","year":"2020","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1016\/j.ndteint.2006.01.005","article-title":"Characterisation of Defects in the Railhead Using Ultrasonic Surface Waves","volume":"39","author":"Edwards","year":"2006","journal-title":"NDT E Int."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ndteint.2014.03.007","article-title":"A New Electromagnetic Acoustic Transducer (EMAT) Design for Operation on Rail","volume":"65","author":"Petcher","year":"2014","journal-title":"NDT E Int."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"181","DOI":"10.3233\/JAE-201531","article-title":"Application of Chirp Pulse Compression Technique to a High-Temperature EMAT with a Large Lift-Off","volume":"65","author":"Shi","year":"2021","journal-title":"Int. J. Appl. Electromagn. Mech."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"102572","DOI":"10.1016\/j.ndteint.2021.102572","article-title":"High-Temperature EMAT with Double-Coil Configuration Generates Shear and Longitudinal Wave Modes in Paramagnetic Steel","volume":"125","author":"Zhai","year":"2022","journal-title":"NDT E Int."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"102437","DOI":"10.1016\/j.ndteint.2021.102437","article-title":"Rapid Detection of Cracks in the Rail Foot by Ultrasonic B-Scan Imaging Using a Shear Horizontal Guided Wave Electromagnetic Acoustic Transducer","volume":"120","author":"Hu","year":"2021","journal-title":"NDT E Int."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"427","DOI":"10.1177\/1045389X15610910","article-title":"Non-Contact Inspection of Rail Surface and Internal Defects Based on Electromagnetic Ultrasonic Transducers","volume":"27","author":"Han","year":"2016","journal-title":"J. Intell. Mater. Syst. Struct."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1016\/j.ndteint.2016.11.008","article-title":"Enhancement of Ultrasonic Signal Using a New Design of Rayleigh-Wave Electromagnetic Acoustic Transducer","volume":"86","author":"Kang","year":"2017","journal-title":"NDT E Int."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"105945","DOI":"10.1016\/j.ultras.2019.06.007","article-title":"The Effect of EMAT Coil Geometry on the Rayleigh Wave Frequency Behaviour","volume":"99","author":"Thring","year":"2019","journal-title":"Ultrasonics"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"102142","DOI":"10.1016\/j.ndteint.2019.102142","article-title":"Electromagnetic Acoustic Transducer Optimisation for Surface Wave Applications","volume":"107","author":"Tkocz","year":"2019","journal-title":"NDT E Int."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1016\/j.sna.2018.03.010","article-title":"Enhancement of EMAT\u2019s Efficiency by Using Silicon Steel Laminations Back-Plate","volume":"274","author":"Ren","year":"2018","journal-title":"Sens. Actuators Phys."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Zhou, J., and Zheng, Y. (2019). Broadband Linear High-Power Amplifier Based on the Parallel Amplification Architecture for Electromagnetic Ultrasonic Guided Wave. Sensors, 19.","DOI":"10.3390\/s19132924"},{"key":"ref_13","first-page":"165","article-title":"Electromagnetic Nondestructive Evaluation (XX)","volume":"Volume 42","author":"Nishimura","year":"2017","journal-title":"Impedance Matching Using Variable Capacitors in Electromagnetic Ultrasonic Flaw Detection"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"084707","DOI":"10.1063\/1.4999446","article-title":"Design and Implementation of Improved LsCpLp Resonant Circuit for Power Supply for High-Power Electromagnetic Acoustic Transducer Excitation","volume":"88","author":"Zao","year":"2017","journal-title":"Rev. Sci. Instrum."},{"key":"ref_15","unstructured":"Ogi, H., Hirao, M., and Ohtani, T. (1997, January 5\u20138). Flaw Detection by Line-Focusing Electromagnetic Acoustic Transducers. Proceedings of the 1997 IEEE Ultrasonics Symposium Proceedings, Toronto, ON, Canada."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"8064","DOI":"10.1109\/JSEN.2018.2863546","article-title":"Optimal Design of Point-Focusing Shear Vertical Wave Electromagnetic Ultrasonic Transducers Based on Orthogonal Test Method","volume":"18","author":"Jia","year":"2018","journal-title":"IEEE Sens. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"341","DOI":"10.3233\/JAE-190021","article-title":"Numerical Evaluation of Focal Position Selection by Line-Focusing Electromagnetic Acoustic Transducer with Experimental Validation","volume":"61","author":"Huang","year":"2019","journal-title":"Int. J. Appl. Electromagn. Mech."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1109\/JSTSP.2007.897055","article-title":"Automatic Radar Waveform Recognition","volume":"1","author":"Lunden","year":"2007","journal-title":"IEEE J. Sel. Top. Signal Process."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1109\/MAES.2016.160071","article-title":"Overview of Radar Waveform Diversity","volume":"31","author":"Blunt","year":"2016","journal-title":"IEEE Aerosp. Electron. Syst. Mag."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1016\/0041-624X(96)80001-A","article-title":"Analog Pulse Compression System for Real-Time Ultrasonic Non-Destructive Testing","volume":"34","author":"Ermolov","year":"1996","journal-title":"Ultrasonics"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/j.ultras.2017.03.001","article-title":"Application of P4 Polyphase Codes Pulse Compression Method to Air-Coupled Ultrasonic Testing Systems","volume":"78","author":"Li","year":"2017","journal-title":"Ultrasonics"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"172","DOI":"10.1016\/j.microrel.2018.12.002","article-title":"High Sensitivity Detection of Ultrasonic Signal for Nondestructive Inspection Using Pulse Compression Method","volume":"92","author":"Mitsuta","year":"2019","journal-title":"Microelectron. Reliab."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1080\/10589759.2017.1371716","article-title":"Low Sidelobe Level and High Time Resolution for Metallic Ultrasonic Testing with Linear-Chirp-Golay Coded Excitation","volume":"33","author":"Zhang","year":"2018","journal-title":"Nondestruct. Test. Eval."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1464","DOI":"10.1177\/1475921718801996","article-title":"Excitation Series Design and Pulse Compression Synthesis for High-Resolution Lamb Wave Inspection","volume":"18","author":"Hua","year":"2019","journal-title":"Struct. Health Monit."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"SG1015","DOI":"10.35848\/1347-4065\/ac49fe","article-title":"Evaluation of Contrast Enhancement Ultrasound Images of Sonazoid Microbubbles in Tissue-Mimicking Phantom Obtained by Optimal Golay Pulse Compression","volume":"61","author":"Hirata","year":"2022","journal-title":"Jpn. J. Appl. Phys."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"256","DOI":"10.1250\/ast.39.256","article-title":"Sensitivity Time Control for Chirp Transmission","volume":"39","author":"Maeda","year":"2018","journal-title":"Acoust. Sci. Technol."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Burrascano, P., Laureti, S., Hutchins, D., Ricci, M., and Senni, L. (2015, January 21\u201324). A Pulse Compression Procedure for the Measurement and Characterization of Non-Linear Systems Based on Exponential Chirp Signals. Proceedings of the 2015 Ieee International Ultrasonics Symposium (IUS), Taipei, Taiwan.","DOI":"10.1109\/ULTSYM.2015.0435"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1109\/TUFFC.2017.2661383","article-title":"Coded Excitation for Pulse-Echo Systems","volume":"64","author":"Isla","year":"2017","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/0924-4247(95)00846-2","article-title":"Sensors Based on Piezoelectric Resonators","volume":"48","author":"Benes","year":"1995","journal-title":"Sens. Actuators-Phys."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"632","DOI":"10.1016\/j.ultras.2013.09.003","article-title":"Analysis of Multiple Wavelengths of Lamb Waves Generated by Meander-Line Coil EMATs","volume":"54","author":"Zhai","year":"2014","journal-title":"Ultrasonics"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1109\/TCT.1973.1083750","article-title":"Acoustic Surface-Wave Transversal Filters","volume":"20","author":"Matthaei","year":"1973","journal-title":"IEEE Trans. Circuit Theory"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1109\/PROC.1971.8180","article-title":"Acoustic Surface Wave Filters","volume":"59","author":"Tancrell","year":"1971","journal-title":"Proc. IEEE"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1049\/ecej:19960204","article-title":"Modern SAW-Based Pulse Compression Systems for Radar Applications. Part 2: Practical Systems","volume":"8","author":"Arthur","year":"1996","journal-title":"Electron. Commun. Eng. J."},{"key":"ref_34","unstructured":"Edmonson, P.J., and Hunt, W.D. (2004, January 22). Surface Acoustic Wave Sensors: Attributes and Advantages. Proceedings of the Rawcon: 2004 IEEE Radio and Wireless Conference, Atlanta, GA, USA."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2411","DOI":"10.1121\/1.422760","article-title":"Line-Focusing of Ultrasonic SV Wave by Electromagnetic Acoustic Transducer","volume":"103","author":"Ogi","year":"1998","journal-title":"J. Acoust. Soc. Am."},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Hirao, M., and Ogi, H. (2017). Electromagnetic Acoustic Transducers: Noncontacting Ultrasonic Measurements Using EMATs, Springer.","DOI":"10.1007\/978-4-431-56036-4"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1109\/TIM.2023.3262252","article-title":"A Method of Rayleigh Wave Combined with Coil Spatial Pulse Compression Technique for Crack Defects Detection","volume":"72","author":"Feng","year":"2023","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Jiang, C.-L., Li, Z.-P., Wang, S.-J., Wang, S.-B., and Yang, R. (2020, January 20\u201322). Meander Line Coil EMAT Based on Spatial Pulse Compression for Rayleigh Waves. Proceedings of the 2020 IEEE Far East NDT New Technology Application Forum (FENDT), Kunming, China.","DOI":"10.1109\/FENDT50467.2020.9337551"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"165","DOI":"10.1109\/TUFFC.2015.2496292","article-title":"Excitation Waveform Design for Lamb Wave Pulse Compression","volume":"63","author":"Lin","year":"2016","journal-title":"IEEE Trans. Ultrason. Ferroelectr. Freq. Control"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Thomas, S., Muazu, H., Zarma, T.A., and Galadima, A. (2017, January 28\u201329). Finite Element Analysis of EMAT Using Comsol Multiphysics. Proceedings of the 2017 13th International Conference on Electronics, Computer and Computation (ICECCO), Abuja, Nigeria.","DOI":"10.1109\/ICECCO.2017.8333338"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Zhang, K., Yi, P., Li, Y., Zhang, X., and Guan, Z. (2014, January 3\u20135). Numerical Investigation of the Lift-Off Effect on the Cut-Off Frequency in the Rayleigh Wave. Proceedings of the 16th International Conference on Mechatronics-Mechatronika 2014, Brno, Czech Republic.","DOI":"10.1109\/MECHATRONIKA.2014.7018293"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/8\/3943\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:15:14Z","timestamp":1760123714000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/8\/3943"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,4,13]]},"references-count":41,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2023,4]]}},"alternative-id":["s23083943"],"URL":"https:\/\/doi.org\/10.3390\/s23083943","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,4,13]]}}}