Frequency Modulated Continuous Wave Radar System at ISM Band for Short Range Indoor Positioning

Frequency modulated continuous wave (FMCW) radar is a technique for obtaining range information from a radar by frequency modulating a continuous signal. The frequency range of FMCW radar varies from 900 MHz to 80 GHz, and one of the applications is human positioning for indoor healthcare scenarios and intelligent housing system. FMCW radar system is becoming more portable, more precise and cheaper. In this thesis, a FMCW radar system at 2.4 GHz ISM band is proposed for intelligent housing system.
The thesis proposes an economic and efficient DDS-based PLL frequency synthesizer. It can generate a frequency modulated continuous wave from 2.4 GHz to 2.5 GHz in 1 ms. The thesis uses the ADF4158 phase locked loop (PLL) chip to implement triangle frequency modulation in order to generate the 2.4 GHz continuous wave signal, and in this frequency synthesizer system, a direct digital synthesizer (DDS) chip is used, as the reference frequency of PLL, to analyze crystal-based PLL and DDS based PLL. The PLL frequency synthesizer shows high accuracy and low phase noise, and it is easy to be controlled by PC.
The FMCW radar system adopts a homodyne transceiver architecture. The thesis shows effective design of each part of the homodyne receiver, including amplifiers, filters and a mixer. The whole transceiver shows the performance in position estimation and tracking objects within 10 meters with less than 2% error.