{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T06:57:04Z","timestamp":1781161024893,"version":"3.54.1"},"reference-count":26,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T00:00:00Z","timestamp":1781049600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Shanxi Provincial Natural Science Research General Program","award":["202503021211125"],"award-info":[{"award-number":["202503021211125"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>Addressing the challenges of electromagnetic compatibility testing and non-destructive inspection of internal structures in miniaturized electronic devices. This paper reports a non-destructive testing method based on wide-field imaging using diamond nitrogen-vacancy (NV) centers, and systematically demonstrates its application on a black-epoxy-encapsulated Universal Serial Bus (USB) flash drive. In the experiment, a swept microwave signal from 2.82 GHz to 2.97 GHz was sequentially injected into the four external interface pins of the USB drive. A bulk diamond served as the quantum sensing layer, and optically detected magnetic resonance (ODMR) was employed to perform wide-field imaging of the microwave field distribution on the surface of the signal lines within a 1 \u00d7 1 mm2 region of interest. The experimental results show that the microwave field distributions corresponding to different interface channels are significantly different. Based on these differences, the connection relationship between each signal line and its corresponding interface pin can be clearly identified, and the differences in field distribution as well as crosstalk characteristics among channels can be revealed. The method established in this work provides an effective technical pathway for non-destructive electromagnetic testing and functional verification of electronic products.<\/jats:p>","DOI":"10.3390\/mi17060711","type":"journal-article","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T05:50:58Z","timestamp":1781157058000},"page":"711","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Microwave Near Field Imaging of Externally Injected Signals in an Encapsulated Electronic Device"],"prefix":"10.3390","volume":"17","author":[{"given":"Qiang","family":"Zhu","sequence":"first","affiliation":[{"name":"State Key Laboratory of Widegap Semiconductor Optoelectronic Materials and Technologies, North University of China, Taiyuan 030051, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yangfan","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Widegap Semiconductor Optoelectronic Materials and Technologies, North University of China, Taiyuan 030051, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xin","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Extreme Environment Optoelectronic Dynamic Testing Technology and Instrument, North University of China, Taiyuan 030051, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2972-9669","authenticated-orcid":false,"given":"Huanfei","family":"Wen","sequence":"additional","affiliation":[{"name":"Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Tang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Widegap Semiconductor Optoelectronic Materials and Technologies, North University of China, Taiyuan 030051, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jun","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Extreme Environment Optoelectronic Dynamic Testing Technology and Instrument, North University of China, Taiyuan 030051, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2105108","DOI":"10.1002\/advs.202105108","article-title":"Highly Plasticized Lanthanide Luminescence for Information Storage and Encryption Applications","volume":"9","author":"Liu","year":"2022","journal-title":"Adv. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1560\/IJC.48.1.9","article-title":"Integrated Microwave and Optical Scanning Probe for Magnetic Resonance Imaging","volume":"48","author":"Sakran","year":"2008","journal-title":"Isr. J. Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2662","DOI":"10.1109\/TMTT.2021.3060756","article-title":"Real-Time Removal of Topographic Artifacts in Scanning Microwave Microscopy","volume":"69","author":"Fabi","year":"2021","journal-title":"IEEE Trans. Microw. Theory Tech."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1267","DOI":"10.1063\/1.113258","article-title":"Imaging Radio-Frequency Fields Using a Scanning SQUID Microscope","volume":"66","author":"Black","year":"1995","journal-title":"Appl. Phys. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"013855","DOI":"10.1103\/PhysRevA.96.013855","article-title":"On-Chip Quantum Tomography of Mechanical Nanoscale Oscillators with Guided Rydberg Atoms","volume":"96","author":"Rost","year":"2017","journal-title":"Phys. Rev. A"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"013425","DOI":"10.1103\/PhysRevA.96.013425","article-title":"Characterizing the Local Vectorial Electric Field near an Atom Chip Using Rydberg-State Spectroscopy","volume":"96","author":"Cisternas","year":"2017","journal-title":"Phys. Rev. A"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"014021","DOI":"10.1103\/PhysRevApplied.17.014021","article-title":"Measurement and Simulation of the Magnetic Fields from a 555 Timer Integrated Circuit Using a Quantum Diamond Microscope and Finite-Element Analysis","volume":"17","author":"Kehayias","year":"2022","journal-title":"Phys. Rev. Appl."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1038\/nphys1969","article-title":"Electric-Field Sensing Using Single Diamond Spins","volume":"7","author":"Dolde","year":"2011","journal-title":"Nat. Phys."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"014057","DOI":"10.1103\/PhysRevApplied.19.014057","article-title":"Radio-Frequency Electric Field Sensing Based on a Single Solid-State Spin","volume":"19","author":"Cheng","year":"2023","journal-title":"Phys. Rev. Appl."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"4904","DOI":"10.1021\/acs.nanolett.9b00900","article-title":"Robust and Accurate Electric Field Sensing with Solid State Spin Ensembles","volume":"19","author":"Michl","year":"2019","journal-title":"Nano Lett."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"4989","DOI":"10.1021\/nl501841d","article-title":"All-Optical Thermometry and Thermal Properties of the Optically Detected Spin Resonances of the NV\u2013 Center in Nanodiamond","volume":"14","author":"Plakhotnik","year":"2014","journal-title":"Nano Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"070801","DOI":"10.1103\/PhysRevLett.104.070801","article-title":"Temperature Dependence of the Nitrogen-Vacancy Magnetic Resonance in Diamond","volume":"104","author":"Acosta","year":"2010","journal-title":"Phys. Rev. Lett."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2738","DOI":"10.1021\/nl401216y","article-title":"High-Precision Nanoscale Temperature Sensing Using Single Defects in Diamond","volume":"13","author":"Neumann","year":"2013","journal-title":"Nano Lett."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"047601","DOI":"10.1103\/PhysRevLett.112.047601","article-title":"Electronic Properties and Metrology Applications of the Diamond NV\u2014Center under Pressure","volume":"112","author":"Doherty","year":"2014","journal-title":"Phys. Rev. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"736","DOI":"10.1038\/nmeth.3449","article-title":"Single-Cell Magnetic Imaging Using a Quantum Diamond Microscope","volume":"12","author":"Glenn","year":"2015","journal-title":"Nat. Methods"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"014097","DOI":"10.1103\/PhysRevApplied.14.014097","article-title":"Magnetic Field Fingerprinting of Integrated-Circuit Activity with a Quantum Diamond Microscope","volume":"14","author":"Turner","year":"2020","journal-title":"Phys. Rev. Appl."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"132700","DOI":"10.1016\/j.optcom.2025.132700","article-title":"High-Fidelity Microwave Field Imaging Using Nitrogen-Vacancy Centers in Diamond","volume":"600","author":"Zhang","year":"2026","journal-title":"Opt. Commun."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"2300465","DOI":"10.1002\/qute.202300465","article-title":"Measurement of Charge State Dynamics in Nitrogen\u2212Vacancy Centers Based on Microwave-Pulses-Assisted Longitudinal Relaxations Balancing of Spin Qutrit","volume":"7","author":"Li","year":"2024","journal-title":"Adv. Quantum Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"165201","DOI":"10.1103\/PhysRevB.91.165201","article-title":"State-Selective Intersystem Crossing in Nitrogen-Vacancy Centers","volume":"91","author":"Goldman","year":"2015","journal-title":"Phys. Rev. B"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"145502","DOI":"10.1103\/PhysRevLett.114.145502","article-title":"Phonon-Induced Population Dynamics and Intersystem Crossing in Nitrogen-Vacancy Centers","volume":"114","author":"Goldman","year":"2015","journal-title":"Phys. Rev. Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"e2500217","DOI":"10.1002\/qute.202500217","article-title":"Optical Detection of Multi-Channel Digital Signals Using Nitrogen-Vacancy Centers Array","volume":"8","author":"Hao","year":"2025","journal-title":"Adv. Quantum Technol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"4060","DOI":"10.1109\/TAP.2019.2948655","article-title":"DRGH Antenna with Improved Gain and Beamwidth Performance","volume":"68","author":"Gerber","year":"2020","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"118919","DOI":"10.1109\/ACCESS.2021.3107914","article-title":"Design of Broadband Double-Ridge Horn Antenna for Millimeter-Wave Applications","volume":"9","author":"He","year":"2021","journal-title":"IEEE Access"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"7164","DOI":"10.1039\/C8CE01533C","article-title":"Synthesis and Characterization of Diamonds with Different Nitrogen Concentrations under High Pressure and High Temperature Conditions","volume":"20","author":"Chen","year":"2018","journal-title":"CrystEngComm"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2450","DOI":"10.1021\/acs.nanolett.5b05304","article-title":"Patterned Formation of Highly Coherent Nitrogen-Vacancy Centers Using a Focused Electron Irradiation Technique","volume":"16","author":"McLellan","year":"2016","journal-title":"Nano Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"2367","DOI":"10.1021\/acs.nanolett.6b05304","article-title":"Nanoscale Imaging of Current Density with a Single-Spin Magnetometer","volume":"17","author":"Chang","year":"2017","journal-title":"Nano Lett."}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/6\/711\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T06:04:06Z","timestamp":1781157846000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/6\/711"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,10]]},"references-count":26,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6]]}},"alternative-id":["mi17060711"],"URL":"https:\/\/doi.org\/10.3390\/mi17060711","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,10]]}}}