A Study On Key Technology Of Microwave And Millimeter-Wave Phase Noise Test System

With the rapid development of the electronic devices such as radar and communications, the requirements for the phase noise of the system have become stricter. Additive phase noise test techniques of microwave and millimeter wave devices are significant in improving the phase noise characteristic of the system.Firstly, the important concepts and characteristics of additive phase noise were introduced in the paper. After comparing several common methods of phase noise test, the basic principles and structure of additive phase noise test system based on phase discrimination method were analyzed in details.Secondly, all the devices used in the test system, such as power spillter, noise-voltage amplifier, phase shifter, phase detector, data acquisition and processing module based on sound card were presented. And then a C-band additive phase noise test system based on phase discrimination method was founded. The characteristic of the system was verified through measuring the system sensitivity after calibration. Measurement result shows that the system exhibits a phase floor of-154dBc/Hz at 20kHz offset for a 4GHz carrier frequency. This system was also used to test the additive phase noise of multi-way parallel amplifiers and the result verifies that the parallel structure can improve the additive phase noise characteristic near the carrier frequency.Finally, the key circuit modules of Ka-band additive phase noise test system were studied. The Ka-band power splitter and the double balanced mixer (phase detector) used in this system were simulated and designed. The test result shows that the power spilitter and the phase detector can satisfy the requirements and it will build the foundation for realization of Ka-band additive phase noise test system.