Improving Noise Figure Measurement

ABSTRACT: The NC346 and NC5000 Series are designed to be used with an HP8970 or similar Noise Figure Meter. The preferred setup for RF frequencies within the range of the meter is shown below in Figure 1. The isolator and LNA are added to reduce measurement uncertainty. The isolator reduces reflected power between the DUT and the test setup. The LNA reduces the noise figure of the test setup. For the wideband case, the isolator may be replaced with a low VSWR attenuator of approximately 6 to 10 dB.