MilliBox is an affordable, modular, flexible mmwave antenna test system, which can be setup easily to measure phased array radiation pattern. Here we are using MilliBox MBX02 compact mmWave chamber with a GIM04-230 positioner, Copper Mountain C4220 USB VNA, Eravant D-Band frequency extender, and Maury Microwave cables to measure the radiation pattern of 20dBi WR6 waveguide horn antennas.