Modelling of horn antennas and detector cavities for the SAFARI instrument at THz frequencies

S. Doherty; N. Trappe; C. O'Sullivan; J. A. Murphy; G. Curran; P. Mauskopf; J. Zhang; S. Withington; D. Goldie; D. Glowaka; P. Khosropanah; M. Ridder; M. Brujin; J. R. Gao; D. Griffin; B. Swinyard; M. Ferlot

doi:10.1117/12.881096

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23 February 2011 Modelling of horn antennas and detector cavities for the SAFARI instrument at THz frequencies

S. Doherty, N. Trappe, C. O'Sullivan, J. A. Murphy, G. Curran, P. Mauskopf, J. Zhang, S. Withington, D. Goldie, D. Glowaka, P. Khosropanah, M. Ridder, M. Brujin, J. R. Gao, D. Griffin, B. Swinyard, M. Ferlot

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Proceedings Volume 7938, Terahertz Technology and Applications IV; 79380J (2011) https://doi.org/10.1117/12.881096
Event: SPIE OPTO, 2011, San Francisco, California, United States

Abstract

Future Far-IR space telescopes, such as the SAFARI instrument of the proposed JAXA/ESA SPICA mission, will use horn antennas to couple to cavity bolometers to achieve high levels of sensitivity for Mid-IR astronomy. In the case of the SAFARI instrument the bolometric detectors susceptibility to currents coupling into the detector system and dissipating power within the bolometers is a particular concern of the class of detector technology considered.¹ The simulation of such structures can prove challenging. At THz frequencies ray tracing no longer proves completely accurate for these partially coherent large electrical structures, which also present significant computational difficulties for the more generic EM approaches applied at longer microwave wavelengths. The Finite Difference Time Domain method and other similar commercially viable approaches result in excessive computational requirements, especially when a large number of modes propagate. Work being carried out at NUI-Maynooth is utilising a mode matching approach to the simulation of such devices. This approach is based on the already proven waveguide mode scattering code "Scatter"² developed at NUI-Maynooth, which is a piece of mode matching code that operates by cascading a Smatrice while conserving power at each waveguide junction. This paper outlines various approaches to simulating such Antenna Horns and Cavities at THz frequencies, focusing primarily on the waveguide modal Scatter approach. Recently the code has been adapted to incorporate a rectangular waveguide basis mode set instead of the already established circular basis set.

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S. Doherty, N. Trappe, C. O'Sullivan, J. A. Murphy, G. Curran, P. Mauskopf, J. Zhang, S. Withington, D. Goldie, D. Glowaka, P. Khosropanah, M. Ridder, M. Brujin, J. R. Gao, D. Griffin, B. Swinyard, and M. Ferlot "Modelling of horn antennas and detector cavities for the SAFARI instrument at THz frequencies", Proc. SPIE 7938, Terahertz Technology and Applications IV, 79380J (23 February 2011); https://doi.org/10.1117/12.881096

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