Alignment fixture for millimeter waveguide

An alignment fixture for handling the precise waveguide connection procedures required in performing gain measurements of millimeter-wave antennas is described. Two versions of the fixture were developed: one for small devices, such as standard gain horns, which can be supported by the fixture, and another for larger devices. These systems, along with a properly-installed flange, can reduce the measurement uncertainty associated with the connection from greater than 1 dB to a few hundredths of a decibel. For measurements in the WR-22 and WR-15 waveguide bands, the overall gain error for millimeter-frequency antenna measurements has decreased from 0.31 dB to 0.10 dB.<>