Measurement System for Millimeter-Wave Antennas With Distributed External Local Oscillators and Mixers

Abstract

A measurement system for a millimeter-wave (mm-wave) antenna is presented here. The topologies of RF subsystems for antenna measurements are reviewed, and the optimum topology for a far-field antenna measurement range for mm-wave antennas is proposed. This topology minimizes the losses of both the Tx and local oscillator (LO) signal paths. In order to verify the proposed topology, a $W$ -band antenna measurement system for a fully anechoic chamber 10 ( $W$ ) m $\times \,\, 13$ ( $L$ ) m $\times \,\, 7.5$ ( $H$ ) m in size is designed and implemented. To provide the optimal LO input power, a test signal supply that compensates for the complicated losses in the LO signal path is also designed and implemented. The optimization procedure of the LO power is described. The performance of the $W$ -band antenna measurement system is evaluated by measuring the complex reflection coefficient and far-field gain of an electro-formed standard gain horn antenna. The measurement results are compared with intercomparison results between National Measurement Institutes. The results are shown to be within accepted uncertainty levels.