A Low Phase Noise Millimeter-wave Frequency Synthesizer Developed

Frequency Synthesizer is one of the core technologies in communication and electronic system. With the development of modern communication technology, frequency synthesizers are required to have wider band, higher resolution, faster frequency switching speed and lower spurious level. Microwave, due to its characteristics, is more and more applied in radar system, guidance, electronic countermeasure, communication system and remote sensing. The purpose of this task is to develop a millimeter wave frequency synthesizer with low phase noise, fine step and low spurs level.Frequency synthesis mainly concerns about the generation of clean signals. In the first part of this thesis we introduce the main architectures used in frequency synthesis, such as in-direct frequency synthesis (Phase-locked loop, PLL), direct digital synthesis (DDS), and the DDS+PLL synthesis. We analyze the main advantages and disadvantages of these architectures, which mainly focus on the phase noise and spurs.Then we create the phase noise model and analyze the spurs of the main elements used in frequency synthesizer, such as PLL, mixer, frequency multiplier and frequency divider, etc. After that we give the procedure of the system-level design of frequency synthesizer.After the system-level analysis of frequency synthesis and the requirements of the project, we propose the schematic of this low phase noise, fine frequency step, and wide-band microwave frequency synthesizer, based on PLL and mixer method.The test results of the project proved the feasibility and validity of the method. The frequency step of the frequency synthesizer is 10 MHz. The output phase noise is -85dBc/Hz@1kHz. And the spurs level is below -60dBc.