OTA G/T Measurements of Active Phased Array Antenna Noise using a Vector Network Analyzer

Abstract

G/T is a common Figure of merit, which replaces noise Figure for active antennas. An active antenna has both antenna gain from the configuration of the elements as well as from active electronic amplification integrated with the antenna. The integration precludes measuring the noise Figure of the active element directly. Active phased-array antennas have many elements, each contributing some noise (uncorrelated) and some signal (correlated). Traditional Y-factor (Hot/Cold) methods don't work well for active antennas; here is introduced a cold-source and calibration method that can measure both the gain of the antenna and the G/T, utilizing a Vector Network Analyzer with integrated noise Figure measurement.