Closed-Form Expressions for the Radiation Properties of Nanoloops in the Terahertz, Infrared and Optical Regimes Lu, B. Q. Nagar, J. Yue, T. Fernández Pantoja, Mario Alberto Werner, Douglas H. Antenna theory Loop antennas Nanotechnology Submillimeter wave technology This work was supported in part by the Spanish Ministry of Education through the Commission Fulbright Program “Salvador de Madariaga” under Grant PR X14/00320, in part by the Spanish and Andalusian Research Programs under Grant TEC2013-48414-C3-01 and Grant P12-TIC-1442, and in part by the Center for Nanoscale Science, NSF Materials Research Science a nd Engineering Center, under Award DMR-1420620 Since the pioneering work of Heinrich Hertz, perfect-electric conductor (PEC) loop antennas for RF appli- cations have been studied extensively. Meanwhile, nanoloops are promising in the optical regime for their applications in a wide range of emerging technologies. Unfortunately, analytical expressions for the radiation properties of conducting loops have not been extended to the optical regime. This paper presents closed-form expressions for the electric fields, total radiated power, directivity, and gain for thin-wire nanoloops operating in the terahertz, infrared and optical regimes. This is accomplished by extending the formulation for PEC loops to include the effects of dispersion and loss. The expressions derived for a gold nanoloop are implemented and the results agree well with full-wave computational simulations, but with a speed increase of more than 300 × . This allows the scientist or engineer to quickly prototype designs and gain a deeper understanding of the underlying physics. Moreover, through rapid numerical experimentation, these closed-form expressions made possible the discovery that broadband superdirectivity occurs naturally for nanoloops of a specific size and material composition. This is an unexpected and potentially transformative result that does not occur for PEC loops. Additionally, the Appendices give useful guidelines on how to efficiently compute the required integrals. 2021-07-08T10:50:20Z 2021-07-08T10:50:20Z 2017 info:eu-repo/semantics/article Lu, B. Q. ; et. al. Closed-Form Expressions for the Radiation Properties of Nanoloops in the Terahertz, Infrared and Optical Regimes. IEEE Transactions on Antennas and Propagation, Volume: 65, Issue: 1, pp. 121- 133, Jan. 2017 [] http://hdl.handle.net/10481/69610 10.1109/TAP.2016.2624150 eng http://creativecommons.org/licenses/by-nc-nd/3.0/ info:eu-repo/semantics/openAccess Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License IEEE