System Considerations and Analog Baseband Design for an FMCW Radar-based Breast Cancer Detection

This paper presents an analog baseband (ABB) realized using discrete components for an FMCW radar system for the detection of breast cancer operating in the K-band from 20 to 25 GHz. The ABB plays a crucial role in an FMCW radar system. It needs to ensure that radar echoes from distant targets can still be detected and that echoes from near targets do not overdrive the analog-digital-converter (ADC) at the end of the signal chain. Due to the highly dispersive breast as the surrounding medium, conventional system calculation approaches cannot be directly applied. Therefore, in this paper we propose the system considerations which lead to the ABB specifications. The ABB consists of four cascaded bandpass filters. The specifications are adressed by properly choosing the filter characteristics. The comparison between simulation and measurement is shown. The ABB achieves a measured peak gain of 86 dB and is operated from a 5 V supply and draws 4.3 mA resulting in 21.5 mW.