{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T04:19:11Z","timestamp":1760242751381,"version":"build-2065373602"},"reference-count":17,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2016,4,21]],"date-time":"2016-04-21T00:00:00Z","timestamp":1461196800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Symmetry"],"abstract":"<jats:p>The improvement in focusing capabilities of a set of annular scatterers arranged in a fractal geometry is theoretically quantified in this work by means of the finite element method (FEM). Two different arrangements of rigid rings in water are used in the analysis. Thus, both a Fresnel ultrasonic lens and an arrangement of rigid rings based on Cantor prefractals are analyzed. Results show that the focusing capacity of the modified fractal lens is better than the Fresnel lens. This new lens is believed to have potential applications for ultrasonic imaging and medical ultrasound fields.<\/jats:p>","DOI":"10.3390\/sym8040028","type":"journal-article","created":{"date-parts":[[2016,4,21]],"date-time":"2016-04-21T10:25:21Z","timestamp":1461234321000},"page":"28","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["An Ultrasonic Lens Design Based on Prefractal Structures"],"prefix":"10.3390","volume":"8","author":[{"given":"Sergio","family":"Casti\u00f1eira-Ib\u00e1\u00f1ez","sequence":"first","affiliation":[{"name":"Departamento de Ingenier\u00eda Electr\u00f3nica, Universitat de Val\u00e8ncia, Avd. de la Universitat s\/n, Burjassot, Valencia 46100, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"Tarraz\u00f3-Serrano","sequence":"additional","affiliation":[{"name":"Centro de Tecnolog\u00edas F\u00edsicas, Universitat Polit\u00e8cnica de Val\u00e8ncia, Camino de Vera s\/n, Valencia 46022, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4395-7473","authenticated-orcid":false,"given":"Constanza","family":"Rubio","sequence":"additional","affiliation":[{"name":"Centro de Tecnolog\u00edas F\u00edsicas, Universitat Polit\u00e8cnica de Val\u00e8ncia, Camino de Vera s\/n, Valencia 46022, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pilar","family":"Candelas","sequence":"additional","affiliation":[{"name":"Centro de Tecnolog\u00edas F\u00edsicas, Universitat Polit\u00e8cnica de Val\u00e8ncia, Camino de Vera s\/n, Valencia 46022, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonio","family":"Uris","sequence":"additional","affiliation":[{"name":"Centro de Tecnolog\u00edas F\u00edsicas, Universitat Polit\u00e8cnica de Val\u00e8ncia, Camino de Vera s\/n, Valencia 46022, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2016,4,21]]},"reference":[{"key":"ref_1","unstructured":"Mandelbrot, B.B. 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