Microwave Imaging Method for Object Localization without Background Measurements

Background measurement dataset is essential for multistatic microwave imaging. Here the background data is the incident field measured in an environment without a target object. However, measuring the incident field in the real-world is challenging. To address this problem, we present a simple statistical method to estimate averaged scattered field from measured total fields. The method assumes that the bias in the total field averages out, making the averaged scattered field a close approximation of the incident scattered field. Experimental validation using a uniform circular array of antennas and a small object in water demonstrated that the proposed method can accurately estimate the incident field. Imaging results using bifocusing method with the estimated scattered field showed high similarity to those using actual incident field, confirming the effectiveness of the proposed method. The results indicate that accurate microwave imaging for small object localization is achievable even without precise background information, by using averaged total scattered fields.