RF Switch-Based Radar Systems for Simultaneous Multi-Target and Multi-Direction Vital Sign Detection

• Main Authors: Guan-WeiFang, 方冠唯
• Other Authors: Chin-Lung Yang
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/28re5j

碩士 === 國立成功大學 === 電機工程學系 === 107 === This thesis proposes a RF switch-based radar system for multi-target and multi-direction vital signs detection simultaneously. Since continuous wave (CW) radar does not have the ability of range resolution, the signals of multiple reflections are mixed together and the phase information cannot be distinguished. In contrast, frequency modulation continuous wave (FMCW) radar has suitable range resolution and relatively simple system architecture. Therefore, FMCW radar has the capabilities of multi-target monitoring and distance information. We use FMCW radar to detect the vital signs of the two targets in various distance simultaneously. By using RF switch as a multiplexer, we can detect multidirection signal in a transceiver instead of multiple radar system. Moreover, switch has the function of mixing. By proposed RF switch-based radar system, we practice low-IF architecture for multi-direction vital signs detection simultaneously. In terms of demodulation, heart rate (HR) is susceptible to the harmonic of respiratory rate (RR). Therefore, we use ensemble empirical mode decomposition (EEMD) algorithm to extract the intrinsic mode functions of RR and HR. Experiments show that, we can improve signal-to-noise ratio (SNR) and accuracy significantly using this algorithm. And the vital sign errors of multiple targets are below 3% averagely.