The Submillimeter Array

Receiver Lab Talks: 2021

Questions: Edward Tong
Time: Wednesday 1:00 PM EDT (5:00 PM UTC)
Where: Zoom

Date Speaker Title Summary
March 3Edward Tong &
John Garrett
Implementation of 2SB ReceiversIn this talk, we will examine how digital signal processing techniques have helped to advance the state-of-the-art of side-band-separating receivers (2SB receivers). These techniques open the possibility for 2SB receivers for wSMA, which will feature a dual IF system, extending from close to DC to 16+ GHz. The goal of the talk is to initiate further discussions to develop a road map for the development and deployment of 2SB receivers for wSMA.
February 24Lingzhen Zeng
Development of orthomode transducers for the wSMAOrthomode transducers (OMTs) are important passive components widely used in millimeter wave and Terahertz band for remote sensing and astronomical observations. By separating the received signal into two orthogonal linearly polarized components, the OMT proves to be an essential for receiver systems designed to observe the two orthogonal polarization simultaneously. In this presentation, I will first summarize the popular OMT designs in millimeter/submillimeter wavebands. Then I will focus on the wSMA OMT design, fabrication, measurement and integration.
February 10Edward Tong
Tuning circuits for SIS mixersThis is a follow-up of the introductory talk I gave in May 2020: "The Superconductor-Insulator-Superconductor mixer -- some basic concepts and history". I will review the different tuning circuits used in SIS mixer design. These circuits tune out the geometrical capacitance of the SIS junction and allow the SIS mixer to deliver quantum-limited sensitivities.
February 3John Garrett
Waveguide Attenuation: Conductor and Dielectric LossIn this talk, we present a new technique to measure waveguide attenuation. We have used this technique to measure the conductor loss of different WR-2.8 waveguides (copper, gold and aluminum) at both room and cryogenic temperatures. We have also measured the loss tangent of different dielectric materials loaded inside a WR-28 waveguide (HDPE, PTFE and nylon).
January 27Kuan-Yu Liu
Replacement SIS mixers for HARP at JCMTReplacement superconductor-insulator-superconductor (SIS) mixer chips have been developed and fabricated for the 16-element Heterodyne Array Receiver Program (HARP) instrument, which operates between 330 and 375 GHz on the James Clerk Maxwell Telescope (JCMT). The availability of these new mixer chips is very important for the repair and upgrade of HARP. Three of the sixteen mixers have been replaced and the results indicate that the performance of these new mixers is as good as the best original mixers.

Previous presentations available here: CfA managed Google Drive