Integrated Fast UWB Time-Domain Microwave Breast Screening

In conventional time-domain ultra-wide band (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 time domain, this paper 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 65nm 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 2mm skin layer and an embedded tumor, is used to experimentally test the feasibility of the noted approach. A localization error of 0.4 cm to 1 cm is achieved using the proposed technique, for tumors, ranging from 0.5 cm to 0.9 cm in diameter. The acquisition time per received signal is 22ms, an order of magnitude less than that of the imaging techniques reported to date.