Development of a new wideband heterodyne receiver system for the Osaka 1.85 m mm–submm telescope: Corrugated horn and optics covering the 210–375 GHz band

The corrugated horn is a high performance feed often used in radio telescopes. There has been growing demand for wideband optics and horns millimeter submillimeter-wave receivers. It improves the observation efficiency allows us to observe important emission lines such as CO multiple excited states simultaneously. However, millimeter/submillimeter band, it challenging create conical with fractional bandwidth of ~60% because wavelength very short, making difficult make narrow corrugations. In this study, we designed good return loss, low cross-polarization, symmetric beam pattern 210-375GHz band (56% bandwidth) by optimizing dimensions was installed on Osaka 1.85-m mm-submm telescope matched frequency-independent optics, simultaneous observations 12CO, 13CO, C18O (J = 2-1, 3-2) were successfully made. paper, describe new design report evaluation results including optics.