{"id":1044,"date":"2015-06-09T05:12:44","date_gmt":"2015-06-09T05:12:44","guid":{"rendered":"http:\/\/hpthz.unist.ac.kr\/?page_id=1044"},"modified":"2024-08-29T07:40:55","modified_gmt":"2024-08-29T07:40:55","slug":"research-area","status":"publish","type":"page","link":"https:\/\/emchoi.unist.ac.kr\/?page_id=1044","title":{"rendered":"Research Area"},"content":{"rendered":"\n\n\n
\"twt\"
\n<\/a>\u00a0\"fw1\"<\/td>\n		\n

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THz sources based on vacuum electron devices are promising for its high power performance with a compact system. In our team, we develop ~300 GHz folded waveguide traveling tube amplifiers, ~100-300 GHz gyrotron oscillators, and high power amplifiers with solid state driver:<\/p>\n

    \n
  1. I.\u00a0Lee et al., “Microscopic analyses of electrical conductivity of micromachined-folded waveguides based on surface roughness measurement for terahertz vacuum electron devices,” IEEE Trans. on Terahertz Science and Technology, vol.8, iss.6 (2018)<\/li>\n
  2. I. Lee\u00a0et al., “Self-driving, energy-recirculating micromachined G-band folded waveguide traveling-wave tube,” IEEE\u00a0Trans.\u00a0Electron Devices, vol.65, iss.8\u00a0(2018)<\/li>\n
  3. A. Sawant\u00a0et al., “Development of the full package of gyrotron simulation code,”\u00a0Jour. of Korean Phys. Soc.\u00a0(2018)<\/li>\n<\/ol>\n

    \uacfc\uc81c\uc9c0\uc6d0: \uad6d\ubc29\uacfc\ud559\uc5f0\uad6c\uc18c, \ud55c\uad6d\uc5f0\uad6c\uc7ac\ub2e8 \ud575\uc735\ud569\uae30\ucd08\uc5f0\uad6c, \ud575\uc735\ud569\uc5f0\uad6c\uc18c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
    \n

    \"fgf\"<\/a><\/p>\n

    \"oamcom\"<\/td>\n

    		\n

    6G E-band \ub300\uc5ed OAM-MIMO \ubb34\uc120 \ud1b5\uc2e0 \uc2dc\uc2a4\ud15c \uc5f0\uad6c<\/h4>\n

    We develop multi-electron beam based E-band TWT for 6G OAM MIMO wireless communication system.<\/p>\n

      \n
    1. A. Sawant\u00a0et al., “Orbital angular momentum (OAM) of rotating modes driven by electrons in electron cyclotron masers,”\u00a0Scientific Reports 7, 3372\u00a0(2017)<\/li>\n<\/ol>\n

      \uacfc\uc81c\uc9c0\uc6d0: \uc0bc\uc131\ubbf8\ub798\uae30\uc220\uc721\uc131\uc0ac\uc5c5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
      \n

      \"\"<\/a><\/p>\n

       <\/p>\n

      \"phase01\"<\/a><\/td>\n

      		\n

      \ud14c\ub77c\ud5e4\ub974\uce20 \uc804\uc790\uae30\ud30c \uc804\uc1a1 \ubc0f \ubaa8\ub4dc\ubcc0\ud658<\/h4>\n

      Security communication link is a very attractive application by using high power millimeter\/THz wave beams. Our team can design and build extremely higher order rotating modes (HOM) or whispering gallery mode (WGM) by using in-house EM code. Current work focuses on generating HOM or WGM and using them as free-space communications.
      \nRelated publications:<\/p>\n

        \n
      1. I. Lee et al., “Accurate identification of whispering gallery mode patterns of gyrotron with stabilized electro-optic imaging system,”\u00a0Phys. Plasm 25, 013116\u00a0(2018)<\/li>\n
      2. A. Sawant et al., “Generation and validation of topological charges of high-power gyrotron orbital angular momentum beams from phase retrieval algorithm,”IEEE Trans. Terahertz Sci. Tech., vol.7, iss.2(2017)<\/li>\n<\/ol>\n

        \uacfc\uc81c\uc9c0\uc6d0: \uad6d\ubc29\uacfc\ud559\uc5f0\uad6c\uc18c, \ud55c\uad6d\uc5f0\uad6c\uc7ac\ub2e8 \uac1c\uc778\uc5f0\uad6c\uc0ac\uc5c5, \ud575\uc735\ud569\uae30\ucd08\uc5f0\uad6c<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
        \n

        \"vna\"<\/p>\n

        \"converter\"<\/td>\n

        		\n

        RF\/\ubc00\ub9ac\ubbf8\ud130\ud30c\/THz \ub300\uc5ed \ubb3c\uc9c8 \ud2b9\uc131 \uc5f0\uad6c<\/h4>\n

        Precise measurement of electromagnetic wave fields is very critical characterizing an antenna performance as well as characterizing material properties.\u00a0We are developing precise dielectric properties measurement technique in the range of tens of GHz to hundreds of GHz.
        \nRelated publications:<\/p>\n

          \n
        1. H. E. Choi et al., “Error tolerant method of dielectric constant measurement using a selective resonance mode at W-band,” IEEE Trans. Microwave Theory and Tech. (2019)<\/li>\n
        2. M. S. Choe et al., “Measuring the carrier lifetime by using a quasi-optical millimeter- and THz-wave system,” Appl. Phys. Lett. 110, 074101 (2017)<\/li>\n
        3. I. Lee et al., “In-situ endoscopic observation of higher-order mode conversion in a microwave mode converter based on an electro-optic probe system,” Opt. Exp. 22 (2014)<\/li>\n
        4. K. H. Kim et al., “Near field pattern of large aperture higher order mode generator using back propagated fields in free space,” IEEE Trans. Plas. Sci. 42 (2014)<\/li>\n<\/ol>\n

          \uacfc\uc81c\uc9c0\uc6d0: \ud55c\uad6d\uc5f0\uad6c\uc7ac\ub2e8 \uc911\uacac\uc5f0\uad6c\uc0ac\uc5c5, \ud575\uc735\ud569\uae30\ucd08\uc5f0\uad6c<\/p>\n

          <\/h4>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n
          \"5\"
          \n<\/a><\/td>\n          		\n

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          Plasma breakdown by Millimeter-wave\/THz sources has been a long time research topic in the plasma community. We are interested in possible detection of standoff radioactive material using a highly focused THz beam.
          \nRelated publications:<\/p>\n

            \n
          1. D. S. Kim et al., “Remote detection of radioactive material using high-power pulased electromagnetic radiation,”\u00a0Nat. Comm.\u00a08,\u00a015394 (2017)<\/li>\n
          2. D. S. Kim et al., “Study on statistical breakdown delay time in Argon gas using a W-band millimeter-wave gyrotron,”\u00a0Phys. Plasm, 23, 043505 (2016)<\/li>\n
          3. D. S. Kim et al., “Numerical estimation on free electrons generated by shielded radioactive materials under various gaseous environments,” AIP Advances 3, 062109 (2013)<\/li>\n<\/ol>\n

            \uacfc\uc81c\uc9c0\uc6d0: \ud55c\uad6d\uc5f0\uad6c\uc7ac\ub2e8 \uac1c\uc778\uae30\ubcf8\uc5f0\uad6c\uc0ac\uc5c5, \uc911\uacac\uc5f0\uad6c\uc0ac\uc5c5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

             <\/p>\n\n\n\n
            <\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

             <\/p>\n","protected":false},"excerpt":{"rendered":"

            \u00a0 \ub9c8\uc774\ud06c\ub85c\uacf5\uc815\uacfc \uc804\uc790\ube54 \uae30\ubc18\uc758 \ud14c\ub77c\ud5e4\ub974\uce20 \uc99d\ud3ed\/\ubc1c\uc9c4\uae30 \uac1c\ubc1c THz sources based on vacuum electron devices are promising for its high power performance with a compact system. In our team, we develop ~300 GHz folded waveguide traveling tube amplifiers, ~100-300 GHz gyrotron oscillators, and high power amplifiers with solid state driver: I.\u00a0Lee et al., “Microscopic analyses of […]<\/p>\n","protected":false},"author":4,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1044","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=\/wp\/v2\/pages\/1044"}],"collection":[{"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1044"}],"version-history":[{"count":69,"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=\/wp\/v2\/pages\/1044\/revisions"}],"predecessor-version":[{"id":6393,"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=\/wp\/v2\/pages\/1044\/revisions\/6393"}],"wp:attachment":[{"href":"https:\/\/emchoi.unist.ac.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}