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Low phase noise RF oscillator with high second harmonic suppression


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Low phase noise RF oscillator with high second harmonic suppression
Zhou WenjunZhang XuefengChen Jianxin
School of Electronics and Information,Nantong University,Nantong 226019
radio frequency feedback oscillator low phase noise bandpass filter complex quality factor second harmonic suppression
As a key component in wireless communication system,the radio frequency(RF)oscillator plays a key role in the frequency up-/down-conversion in the RF front end.In order to meet the requirements of the system improvements,this paper proposes a method to design a low phase noise feedback oscillator with the high second harmonic suppression.A bandpass filter is introduced between the input and output of the amplifier for constructing a feedback loop.The phase noise of the oscillator can be effectively improved due to its large complex quality factor(peak QSC)in the passband.Then a pair of λg/8 open-and short-circuited stubs in parallel is added to the output of the oscillator in order to effectively suppress the second harmonic while there is no effect on the fundamental signal.The measured and simulated results show good agreement.The low phase noise and second harmonic suppression are simultaneously realized in the proposed oscillator.


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Last Update: 2015-08-31