Research On Photonics-Assisted Novel Microwave Phase Noise Measurement Technique

Microwave sources are the core of wireless communication,electronic measurement,radar,navigation and electronic warfare.Phase noise is one of the most important parameters used to characterize the quality of microwave sources.Accurate microwave phase noise measurement will play an important role in promoting the development of microwave systems.With the continuous development of microwave signal sources to higher frequency,broader bandwidth and lower phase noise,traditional phase noise measurement methods are faced with severe challenges in measurement accuracy,measurement sensitivity and frequency measurement range.Microwave photonics endows the phase noise measurement method with the advantages of higher frequency,larger bandwidth,higher sensitivity,electromagnetic immunity and so on.However,the present photonic-delay-line-based frequency discriminator phase noise measurement methods face issues such as narrow measurement bandwidth,single functionality,and low measurement efficiency,which limits their popularization in practical applications.Based on this background,the thesis studies the photonics-assisted novel microwave phase noise measurement technique.The main innovative contributions are as follows:1.Aiming at the limitations of the operational bandwidth,a wideband microwave phase noise measurement method based on photonic time delay and frequency-conversion delay matching is proposed.The prominent advantage of this scheme lies in that the signal under test can be processed at a lower frequency range by frequency conversion,thus relieving the limitation of electrical devices on operational bandwidth.Furthermore,the additional phase noise introduced by the reference source can be effectively eliminated through matching the time delay of two down-conversion branches.Experimental results demonstrate the reliability and advantages of this method,achieving accurate measurement of phase noise in 10-40 GHz microwave signals,with a measurement sensitivity of-134.13 dBc/Hz@10 kHz.2.Aiming at the issue of single functionality,a dual-functional system for signal generation and phase noise measurement is proposed.The system includes a signal generation module and a phase noise measurement module,which share an electroabsorption modulated laser,making the system cost-effective and simple in structure.Experimental results show that the dual-functional system can generate a high-performance microwave signal and provide a convenient solution for measuring the phase noise of the microwave signal.3.Aiming at the issue of low measurement efficiency,an automated phase noise measurement system is proposed.The orthogonal phase control module is designed and the supporting program is developed,which can realize the automatic phase orthogonal of two input signals of the phase detector as well as real-time calculation of phase noise of the signal under test.The hardware modules are packaged,and the measuring prototype is prepared.The experimental results show that the prototype can realize the fast and accurate measurement of the phase noise of the signal to be measured and improve the measurement efficiency.