A Wideband Millimeter-wave Receiver at 210-350 GHz for LMT-FINER
arXiv:2606.25637
The paper describes the design and initial laboratory testing of a wideband 210‑350 GHz dual‑polarization sideband‑separating receiver for the Large Millimeter Telescope, showing ~100 K noise temperature and ~20 dB image rejection using SIS mixer technology.
Abstract
The Far-Infrared Nebular Emission Receiver (FINER) project is developing two wideband dual-polarization sideband-separating receivers covering 120-210 GHz and 210-350 GHz to efficiently identify high-redshift galaxy candidates in the early universe. Based on high-critical-current-density superconductor-insulator-superconductor mixer technology originally developed for the ALMA wideband sensitivity upgrade, the FINER receivers are designed to provide an intermediate-frequency bandwidth of 3-21 GHz per sideband and per polarization, approximately five times wider than the current ALMA specifications. After installation on the Large Millimeter Telescope, these receivers are expected to offer highly efficient spectral-scanning capability among (sub)millimeterwave facilities in the northern-hemisphere. This paper reports the initial laboratory characterization of the 210-350 GHz receiver. The measured single sideband receiver noise temperature is approximately 100 K over most of the radio-frequency band. Digital sideband separation was also demonstrated using a wideband spectrometer array (DRS4), achieving an image rejection ratio of around 20 dB in the initial tests. These results represent an important step toward the realization of a wideband spectral-scanning receiver system for FINER.
5 pages, 3 figure, Proceeding paper presented in SPIE Astronomical Telescope and Instrumentation 2026