The conceptual design of multi-channel millimeter wave receiver for VLBI

The most important thing in millimeter and sub-millimeter wave VLBI is how to calibrate the variations in the phase of an electromagnetic wave propagating through the troposphere. Many techniques for calibrating the phase fluctuations due to the troposphere have been well proposed and demonstrated (Alef, W. et al., 2003; Asaki, Y. et al., 1998; Sasao, T., 2002). A millimeter wave multi-channel receiver system which can be used for phase calibration in millimeter and sub-millimeter wave VLBI observation is proposed. A conceptual multi-channel receiver system and quasi-optical filters which could be used in this receiver are described.