Poster Presentation
Characterization of diplexer noise contribution at 4 K
Presenter: Sihyun Lee (Korea Astronomy and Space Science Institute)
Dichroic filters are crucial components for enabling simultaneous multi-frequency observations by optically separating the lower-frequency bands—mainly used for phase calibration—from the higher-frequency bands. In the KVN system, these dichroic filters, specifically the type currently implemented at KVN sites, require additional optical components, which in turn increase the optical path length and degrade beam alignment accuracy.
Meanwhile, a diplexer reduces beam alignment errors by reducing the number of optical components. However, it contributes to receiver noise temperature, which can degrade the receiver sensitivity. We measured a difference in noise temperature with and without the diplexer at 4 K. In this presentation, we will discuss the noise contribution by the diplexer and its implications for system performance.
asiaa.sinica.edu.tw