Design Of Wide Tuning Range And Low Phase Noise Voltage Controlled Oscillator Chip

Recent years,the technology boom caused by the 5G communication and IoT system has promoted the research and development of the wireless communication system.With the continuous updating and improvement of communication standards,the performance requirements for the RF transceiver of wireless communication systems are growing with each passing day.Voltage-control-oscillator is one of the most crucial parts of a wireless transceivers,it provides stable local oscillation signal for the wireless transceiver and participate in the signal modulation and demodulation processes.Its performance,eg.phase noise,tuning range and power consumption,have great effect on the wireless transceiver's performance.Designing a monolithic integrated VCO with wide frequency band and good phase noise has become the focus of people's attention in recent years.In consideration of the aforementioned problems,the theory and design methdologies of VCO are studied.Many domestic and overseas references on wide tuning range as well as low phase noise VCO have been reviewed.Design methodologies on wide tuning range of the VCO are analysised.Based on different kinds of IC process,two wide tuning range and low phase noise VCO chips are designed.To meet the requirement of the NB-IoT communication application,a boardband low phase noise VCO with 2 times NB-IoT frequency band is designen.Due to the low power consideration of the whole NB-IoT system,a 55 nm CMOS LPe process based on silicon is selected for the low dissipation design.This design employed switched capacitor array technology to extend the tuning range of the designed VCO.To realize good phase noise performance under low power working condition,a Class-C structure is envolved.In addition,a transformer inductor is employed to replace the traditional differencial inductor to enhance the quality factor of the LC tank and to achieve good phase noise.Trageted on the special aviation application demand,a 10 GHz~20 GHz wide tuning range VCO is designed.The design is based on 0.15 ?m GaAs process in consideration of the high oscillation frequency,good phase noise as well as high output power requirement.It has also required that the VCO only use one single control voltage to realize continuous tuning.After comprehensively comparing the varactor radio and quality factor of the on-chip varactor and off-chip varactor,the off-chip scheme and Multi-chip-Module(MCM)technology are selected.The off-chip scheme is realized by placing the variable capacitance part of the LC tank off-chip,using a high performance off-chip varactor,placing the rest of the circuits on the chip,and then the two part are integrated and uniformly packaged with flip-chip process.By adopting high varactor ratio and high quality factor off-chip varactor,the characteristics of 10 GHz wide frequency tuning band and-90 dBc/Hz@100kHz low phase noise is achieved.