{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,30]],"date-time":"2026-03-30T12:11:43Z","timestamp":1774872703402,"version":"3.50.1"},"reference-count":42,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2023,3,22]],"date-time":"2023-03-22T00:00:00Z","timestamp":1679443200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["317116"],"award-info":[{"award-number":["317116"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This work details an effective dynamic chemical etching technique to fabricate ultra-sharp tips for Scanning Near-Field Microwave Microscopy (SNMM). The protruded cylindrical part of the inner conductor in a commercial SMA (Sub Miniature A) coaxial connector is tapered by a dynamic chemical etching process using ferric chloride. The technique is optimized to fabricate ultra-sharp probe tips with controllable shapes and tapered down to have a radius of tip apex around \u223c1 \u03bcm. The detailed optimization facilitated the fabrication of reproducible high-quality probes suitable for non-contact SNMM operation. A simple analytical model is also presented to better describe the dynamics of the tip formation. The near-field characteristics of the tips are evaluated by finite element method (FEM) based electromagnetic simulations and the performance of the probes has been validated experimentally by means of imaging a metal-dielectric sample using the in-house scanning near-field microwave microscopy system.<\/jats:p>","DOI":"10.3390\/s23063360","type":"journal-article","created":{"date-parts":[[2023,3,23]],"date-time":"2023-03-23T02:35:26Z","timestamp":1679538926000},"page":"3360","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Fabrication of Ultra-Sharp Tips by Dynamic Chemical Etching Process for Scanning Near-Field Microwave Microscopy"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0251-5975","authenticated-orcid":false,"given":"C. H.","family":"Joseph","sequence":"first","affiliation":[{"name":"Institute for Microelectronics and Microsystems, National Research Council (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"},{"name":"Department of Electronic Engineering, University of Rome \"Tor Vergata\", Via del Politecnico 1, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5770-0380","authenticated-orcid":false,"given":"Giovanni","family":"Capoccia","sequence":"additional","affiliation":[{"name":"Institute for Microelectronics and Microsystems, National Research Council (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1281-0409","authenticated-orcid":false,"given":"Andrea","family":"Lucibello","sequence":"additional","affiliation":[{"name":"Institute for Microelectronics and Microsystems, National Research Council (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9547-4265","authenticated-orcid":false,"given":"Emanuela","family":"Proietti","sequence":"additional","affiliation":[{"name":"Institute for Microelectronics and Microsystems, National Research Council (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3850-2685","authenticated-orcid":false,"given":"Giovanni Maria","family":"Sardi","sequence":"additional","affiliation":[{"name":"Institute for Microelectronics and Microsystems, National Research Council (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9113-3957","authenticated-orcid":false,"given":"Giancarlo","family":"Bartolucci","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, University of Rome \"Tor Vergata\", Via del Politecnico 1, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4815-9470","authenticated-orcid":false,"given":"Romolo","family":"Marcelli","sequence":"additional","affiliation":[{"name":"Institute for Microelectronics and Microsystems, National Research Council (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,3,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"044304","DOI":"10.1063\/1.2234801","article-title":"Effect of tip geometry on contrast and spatial resolution of the near-field microwave microscope","volume":"100","author":"Imtiaz","year":"2006","journal-title":"J. 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