{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T22:34:19Z","timestamp":1789166059046,"version":"build-2803163510"},"reference-count":24,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2023,4,29]],"date-time":"2023-04-29T00:00:00Z","timestamp":1682726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery","doi-asserted-by":"publisher","award":["RGPIN6570"],"award-info":[{"award-number":["RGPIN6570"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery","doi-asserted-by":"publisher","award":["RGPIN-2017-04974"],"award-info":[{"award-number":["RGPIN-2017-04974"]}],"id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Herein, we present new design principles for gain enhancement and cross-polarization suppression in dual-polarized cavity-backed antennas and demonstrate the capability in an octagonal cavity-backed open prism antenna (OCROP). In our approach, the gain is enhanced through an optimal flaring procedure and a novel metallic iris is used to control the electromagnetic fields and thereby reduce the cross-polarization. Previously, we investigated a dual-polarized OCROP antenna configuration and were able to simultaneously achieve 50% impedance bandwidth, 40% cross-polarization bandwidth (\u226425 dB), and 10.2 dBi peak gain. In this study, we investigated gain enhancement by flaring an upper section of the ground cavity sidewalls, while maintaining a constant cavity height. Two cases were investigated: (1) the flare angle was modified, while the ratio of the non-flared to flared sidewall heights was kept constant, and (2) the ratio of the non-flared to flared sidewall heights was varied. In case 1, we established that, while increasing the flare angle results in a gain increase, there is a limit, as cross-polarization at the upper operating frequencies increases. In case 2, we were able to reduce the aperture phase error and achieve a higher peak gain of 12.8 dBi. To address the increased cross-polarization at the high frequency end when a large flare was used, we added a metallic iris at the junction of non-flared and flared sidewalls. We showed that increasing the iris width generally decreases the cross-polarization at high frequencies, without compromising the gain and impedance bandwidth. At an optimal width, it provides a nearly constant, low cross-polarization (below \u221225.8 dB) and a peak gain of 13.3 dBi, across the entire 50.7% impedance bandwidth of the antenna. We fabricated and successfully tested a prototype to verify the design and simulation approach. These results prove that incorporating an aperture flare with a metallic iris can significantly improve the gain and cross-polarization performance of cavity-backed antennas.<\/jats:p>","DOI":"10.3390\/s23094389","type":"journal-article","created":{"date-parts":[[2023,5,1]],"date-time":"2023-05-01T12:12:11Z","timestamp":1682943131000},"page":"4389","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Gain Enhancement and Cross-Polarization Suppression of Cavity-Backed Antennas Using a Flared Ground Cavity and Iris"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8314-360X","authenticated-orcid":false,"given":"Yanxia","family":"Liu","sequence":"first","affiliation":[{"name":"Department of Electrical & Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9349-8076","authenticated-orcid":false,"given":"Dustin","family":"Isleifson","sequence":"additional","affiliation":[{"name":"Department of Electrical & Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada"},{"name":"Centre for Earth Observation Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lotfollah","family":"Shafai","sequence":"additional","affiliation":[{"name":"Department of Electrical & Computer Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3157","DOI":"10.1109\/TAP.2010.2055792","article-title":"Wideband and high-gain composite cavity-backed crossed triangular bowtie dipoles for circularly polarized radiation","volume":"58","author":"Qu","year":"2010","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Liu, Y., Isleifson, D., and Shafai, L. (2023). Wideband Dual-Polarized Octagonal Cavity-Backed Antenna with Low Cross-Polarization and High Aperture Efficiency. Sensors, 23.","DOI":"10.3390\/s23020731"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Liu, Y., Isleifson, D., and Shafai, L. (2021, January 8\u201311). Frequency Scalability of the Dual-polarized Flat-wire Open Loop Antennas. Proceedings of the IEEE 19th ANTEM, Winnipeg, MB, Canada.","DOI":"10.1109\/ANTEM51107.2021.9518605"},{"key":"ref_4","unstructured":"Balanis, C. (2016). Antenna Theory: Analysis and Design, John Wiley & Sons."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Liu, Y.I.D., and Shafai, L. (2021, January 8\u201311). A Triangularly Packed Planar Array of Dual-polarized L-band Flat-wire Open Loop Antennas. Proceedings of the IEEE 19th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM), Winnipeg, MB, Canada.","DOI":"10.1109\/ANTEM51107.2021.9518519"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"153479","DOI":"10.1016\/j.aeue.2020.153479","article-title":"A compact high-performance patch array with suppressed cross polarization using image feed configuration","volume":"127","author":"Karami","year":"2020","journal-title":"AEU-Int. J. Electron. Commun."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Abdalmalak, K., Althuwayb, A., Lee, C., Botello, G., Falc\u00f3n-G\u00f3mez, E., Garc\u00eda-Castillo, L., and Garc\u00eda-Mu\u00f1oz, L. (2022). Standing-Wave Feeding for High-Gain Linear Dielectric Resonator Antenna (DRA) Array. Sensors, 22.","DOI":"10.3390\/s22083089"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1979","DOI":"10.1109\/TAP.2006.877172","article-title":"Array thinning by using antennas in a Fabry\u2013Perot cavity for gain enhancement","volume":"54","author":"Gardelli","year":"2006","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1109\/TAP.2011.2173113","article-title":"The use of simple thin partially reflective surfaces with positive reflection phase gradients to design wideband, low-profile EBG resonator antennas","volume":"60","author":"Ge","year":"2011","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Liu, Y., Shafai, L., and Isleifson, D. (2021, January 8\u201311). Excessive Aperture Efficiency of Compact Antennas Demonstrated by Waveguides and Small Horns. Proceedings of the IEEE 19th ANTEM, Winnipeg, MB, Canada.","DOI":"10.1109\/ANTEM51107.2021.9518998"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1109\/TAP.1958.1144605","article-title":"Effect of antenna size on the gain and beamwidth of directional antennas","volume":"6","author":"Harrington","year":"1958","journal-title":"IRE Trans. Antennas Propag."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Silver, S. (1984). Microwave Antenna Theory and Design, Peter Peregrinus.","DOI":"10.1049\/PBEW019E"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"827","DOI":"10.1109\/TAP.2002.1017663","article-title":"Broadband probe-fed patch antenna with a W-shaped ground plane","volume":"50","author":"Wong","year":"2002","journal-title":"IEEE Trans. Antennas Propag."},{"key":"ref_14","unstructured":"Healthwise (2021, December 20). Eye Anatomy and Function. Available online: https:\/\/www.uofmhealth.org\/health-library\/hw121946."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Olver, A., Clarricoats, P., Kishk, A., and Shafai, L. (1994). Microwave Horns and Feeds, The Institute of Electrical and Electronics Engineers.","DOI":"10.1049\/PBEW039E"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Rudge, A., Milne, K., Olver, A., and Knight, P. (1982). The Handbook of Antenna Design, Peter Peregrinus. Chapter 4.","DOI":"10.1049\/PBEW015F"},{"key":"ref_17","unstructured":"Shafai, L., and Kishk, A. (1989). Handbook of Microstrip Antennas, Peter Peregrinus. Chapter 2."},{"key":"ref_18","unstructured":"Shafai, L., and Volakis, J.L. (2007). Antenna Engineering Handbook, McGraw-Hill Education. Chapter 16."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Ferreira-Gomes, B., Oliveira, O., and Mej\u00eda-Salazar, J. (2021). Chiral dielectric metasurfaces for highly integrated, broadband circularly polarized antenna. Sensors, 21.","DOI":"10.3390\/s21062071"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Chietera, F., Colella, R., and Catarinucci, L. (2021). Dielectric resonators antennas potential unleashed by 3D printing technology: A practical application in the IoT framework. Electronics, 11.","DOI":"10.3390\/electronics11010064"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"843","DOI":"10.3390\/eng4010051","article-title":"A Review of Dielectric Resonator Antenna at Mm-Wave Band","volume":"4","author":"Alanazi","year":"2023","journal-title":"Eng"},{"key":"ref_22","unstructured":"(2023, April 18). NARDA-ATM Standard and High Gain Horn Antenna for RF Microwave. Available online: https:\/\/www.atmmicrowave.com\/waveguide\/horn-antenna-standard-gain-wide-band\/."},{"key":"ref_23","unstructured":"Long, D., and Ulaby, F. (2014). Microwave Radar and Radiometric Remote Sensing, University of Michigan Press."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3074","DOI":"10.1109\/TAP.2020.3030922","article-title":"Decoupling between extremely closely spaced patch antennas by mode cancellation method","volume":"69","author":"Sun","year":"2020","journal-title":"IEEE Trans. Antennas Propag."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/9\/4389\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T19:26:29Z","timestamp":1760124389000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/9\/4389"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,4,29]]},"references-count":24,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2023,5]]}},"alternative-id":["s23094389"],"URL":"https:\/\/doi.org\/10.3390\/s23094389","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,4,29]]}}}