Groves, PatriciaConroy, PhilipBelostotski, LeonidOkoniewski, Michal2025-01-312025-01-312016-11Groves, P., Conroy, P., Belostotski, L., & Okoniewski, M. (2016). Antenna Two-Port Electrical and noise parameters. IEEE Antennas and Wireless Propagation Letters, 16, 1265–1268. https://doi.org/10.1109/lawp.2016.2631942https://doi.org/10.1109/LAWP.2016.2631942https://hdl.handle.net/1880/120608Noise correlation matrices and noise parameters are useful for low-noise amplifier designers seeking to achieve the best noise performance out of their circuits. In some applications, such as radio astronomy, antennas and antenna arrays are part of receivers and, thus, modeling of the antenna noise is useful. Currently, antenna noise is modeled through antenna efficiency. A more accurate information on the highest-possible antenna efficiency is obtained from its S-parameters or noise parameters. In this letter, we show how the two-port S-parameters of an antenna can be determined by measuring its reflection coefficients inside two specifically sized Wheeler caps, in addition to a free-space measurement. We use the measurement to determine the noise correlation matrices and noise parameters of an antenna. The challenges of constructing appropriately sized Wheeler caps are discussed, and a new way of constructing a Wheeler cap is shown.enUnless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Attribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Antenna efficiencyantenna measurementsnoise parametersWheeler capArticle10.1109/LAWP.2016.2631942