Design and Implementation of 2.4GHz FMCW Radar Circuit

Through the concept of integration of design and test, a 2.4 GHz frequency-modulated continuous wave (FMCW) radar circuit is implemented. The main idea of this work is to set sub-circuits and test points under the full consideration of radar circuit. It not only gives more flexibility to understand and debug the sub-circuits but also implement the radar circuit more efficiently and reliably. The FMCW radar circuit consists of a signal modulation control circuit, a RF signal circuit, transmitting and receiving antennas, an IF signal processing circuit, and a power supply circuit. The implemented sub-circuits include a sawtooth generator, a voltage controlled oscillator, attenuators, a resistive power divider, power amplifiers, low noise amplifiers, a mixer, a low pass filter and operational amplifiers. A Matlab program of Fourier transformation is written to process the IF signals. Under the fully understanding of related devices and circuit planning, the implementation of a 2.4 GHz FMCW radar circuit is completed in one trial. We believe this experience can be applied to other microwave circuits. The first chapter briefly introduces the basic principle and configuration of the FMCW radar circuit. The second chapter depicts the characteristics of devices used in the radar circuit, and the design and measurement results of the sub-circuits. For designers who are already familiar with the characteristics of related devices, fabrication process, soldering considerations, and design formulas, they can progress to the next chapter. The third chapter describes the various stages of the integration and test of the radar circuit. A field test of the radar circuit and a ""2×2"" circularly polarized antenna array is conducted. The fourth chapter gives the conclusion and suggestion for the future work.