Integrated Fast UWB Time-Domain Microwave Breast Screening

In the conventional time-domain ultra-wideband (UWB) imaging in the GHz range, the received signal is sampled and digitized at a very high rate of tens of GHz. This complicates the imaging platform and increases the costs. Instead of digitizing the full signal in the time domain, this article proposes that only a few peak values of the receiver signal and their corresponding incident-time stamps can be digitized and analyzed, resulting in sufficient information for successful imaging. This reduces the receiver complexity as well as the acquisition time. The proposed technique is implemented as an integrated circuit (IC) in a TSMC 65-nm CMOS technology. Consequently, the receiver block only requires the designed receiver IC as well as a microcontroller to digitize the output data of the IC and transfer them to the computer, and thus, it significantly simplifies the receiver block. A tissue-mimicking phantom, consisting of a 10-cm fat cylinder, with a 2-mm skin layer and an embedded tumor, is used to experimentally test the feasibility of the noted approach. A localization error of 0.4–1 cm is achieved using the proposed technique, for tumors, ranging from 0.5 to 0.9 cm in diameter. The acquisition time per received signal is 22 ms, an order of magnitude less than that of the imaging techniques reported to date.