The Research On Low Phase Noise Oscillator Based On Planar Circuit Structure

At present,mobile phones,computers,smart wearable devices and many other wireless communications products are used in many aspects of our life,the number of wireless products is experiencing explosive growth.Thus,the frequency of resources is becoming more and more serious,and the electromagnetic interference between different systems becomes more and more serious.In this case,the wireless communication system with anti-interference,fast transmission,portable and low consumption is a hotspot in the reserch of wireless communication.As the signal generating part of the whole system,the oscillator and frequency source have an important position in the development of the whole system.Therefore,it is of great significance for the reserch of low cost and high performance oscillators.The substrate integrated waveguide(SIW)is a new technology of microwave structure,compared with microstrip,it has the advantages of low loss,high quality factor.Compared with the dielectric resonator,SIW can be integrated with some novel planar circuit structures such as defected ground structure(DGS)and complementary split ring resonator(CSRR)integration.In this paper,the theory and working mechanism of parallel feedback oscillator and series feedback oscillator are described.In addition,the phase noise of the oscillator is reserched and analyzed,and the method to improve the phase noise of the oscillator is proposed.In order to improve the performance of SIW oscillator.Based on the substrate integrated waveguide and evanescent mode theory,this paper introduces the defected ground structure to realize the transmission of evanescent mode.According to the defected ground structure,we design a SIW reasonator.In addition,two parallel feedback oscillator are designed by using the SIW evanescent mode reasonator?The harmonic suppression of these two oscillators are highly improved.In this paper,by etching of CSRR structure in single resonator design,the Q value of the resonator are increased.A series feedback oscillator is designed by using the CSRR resonator.With the comparison of traditional single loaded resonator oscillator,the phase noise of the oscillator has been improved.Finally,this paper introduces the basic principle of phase locked frequency source,a frequency source with a frequency range of 2.5GHz-3.5GHz is designed.In the design of the resonators,oscillators and frequency source,many kinds of electromagnetic simulation software are used in the optimizing and simulating process.All of the design are made by PCB process,the test results meet the design target,which proves the correctness of the related theory and design.