An active cold load (ACL) and an active hot load (AHL) circuit were developed in W-band (75 - 110 GHz) and manufactured in IAF's metamorphic high electron mobility transistor (mHEMT) technology. The millimeter-wave monolithic integrated circuits (MMICs) were radiometricly characterized with a dedicated hot cold on wafer noise measurement setup and packaged into waveguide modules. The active load modules were then again characterized, to be used as reference loads in radiometry systems with switching front-ends [1].