A Compact Digital Low-IF Dual-PLL Doppler Radar for Remote Vital Sign Detection

In this paper, a compact digital 1ow-IF Doppler radar using two phase-locked loops (PLLs) is proposed to remotely detect vital sign signal of the human subject. The system operates at 2. 41GHz with -6.5dBm transmitting power. By feeding the two PLLs with the same reference signal and configuring them to operate at different frequencies, a l-kHz low- IF signal can be achieved without quadrature mix...