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\bibitem{Hesler_etal1999} Hesler, J. L., Hui, K., \& Crowe, T. W. (1999). A fixed{\textendash}tuned 400 GHz subharmonic mixer using planar Schottky diods. In \textit{Proc. 10$^{th}$ Int. Symp. Space Terahertz Technol.} (95). Charlottesville, Virginia, USA.

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