Experimental Measurement of Noise Figure and Radiation Efficiency With the Antenna Y-Factor Method at X-Band

To optimize the design of a high-sensitivity receiver, it is valuable to be able to assign noise budget contributions to various parts of the system. The system noise and aperture efficiency can be characterized using the antenna Y-factor method, which has been added recently to the IEEE Recommended Practice for Antenna Measurements, Std 149-2021. We extend the antenna Y-factor method by showing that it can be used to measure the noise figure of an active antenna and receiver system. With an additional measurement of the receiver noise, the antenna radiation efficiency can be determined. We demonstrate the extended antenna Y-factor method experimentally at X-band for antennas under test, including a horn with near 100% efficiency, microstrip patch antenna with efficiency near 80%, and a patch antenna array with 40% nominal efficiency.