Cramér-Rao-Bound-Based Sensitivity Analysis and Verification of a Digital Microwave Radiometer

Radiometric sensitivity describes the resolution capabilities of a radiometric system and is, therefore, one of the most important properties of a total power radiometer. This study investigates how different nonidealities influence this quality measure, both theoretically and through simulations and measurements. The novelty of this work lies in applying the theoretical framework of the Cramér-Rao lower bound to derive the sensitivity of a digital total power radiometer. Various receiver chain imperfections, such as additive receiver noise, gain variations, phase noise, and quantization noise, are incorporated into the derivation. Additionally, a suboptimal, yet practically relevant estimator is evaluated for its estimation capabilities.