Microwave imaging based on UWB pulses can detect breast cancer, even at an initial stage. To favor the adoption of this method in screening campaigns, it is necessary to replace the expensive and bulky RF instrumentation used so far with ad-hoc designed circuits and systems. In this paper we report on a possible design solution that aims to integrate many of the components in CMOS integrated circuits. Having this as final goal of our MICENEA project, we preliminary assessed the system-level performance of a few critical blocks of the UWB receiver: a slot antenna, the LNA, and the track-and-hold amplifier, the latter two implemented in a CMOS 130nm technology. We developed a simulator that allows us to mix blocks described at circuit-level with blocks described at behavioral level and that simulates a full system, from UWB source to the breast image. We can observe the effect on the final image of non-idealities, like circuit-level limitations and various noise sources, as well as evaluate image quantitative metrics. We report results that show very good system-level performance-only marginally affected by such non-idealities-and that prove the effectiveness of our circuit-level choices and design methodology.