Time-Domain Ultra-Wideband Synthetic Imager (TUSI)
Amin Arbabian, Bagher Afshar, Jun-Chau Chien, Steven Callender, Ali Niknejad and Shinwon Kang
National Science Foundation and Various other sources.
Cancer is the second leading cause of death in the U.S. and the world. Detection in early stages has proven to be essential for reducing the mortality rate. Medical imaging techniques are used to detect and classify potential cancerous tissues by the "traces" that are left from the abnormal cells. Depending on the imaging modality, tumor biology, and the physical parameters involved in the system, the effectiveness of the provided visualization for the process of detection is examined.
The focus of this research is to use the contrast in microwave signals to various tissue abnormalities for the early detection of cancer. In order to achieve this, a large bandwidth is required to provide adequate lateral resolution. UWB signaling provides greater frequency information as well as sufficient tissue penetration, but requires a careful design to address concerns in various system blocks, from signal generation to detection and interpretation. To address the BW issue, frequencies in the sub-THz region are explored and the design of silicon based circuits in that frequency range investigated.
In the initial phase of the project, blocks of this system have been designed and tested. For the desired bandwidth, a distributed amplifier (DA) is designed to meet the specifications. A new method and architecture is proposed for the design of wideband, high gains DAs. As a proof of concept, a DA in the 12-74 GHz range with 19 dB of gain is designed in a digital 90 nm CMOS technology. Also, phased array architectures have been designed and investigated for the desired bandwidth. The system incorporates a wideband front-end, mm-wave frequency-agile PLL, and baseband signal processing consisting of a high resolution sampler and data converter and the interface to the external processor.
Figure 1: Die Micrograph of the TUSI Transmitter