Research And Design Of 140/220GHz Millimeter-wave Voltage-controlled Oscillator

With the growing maturity of wireless communication technology,the demand for wireless transmission by users is also increasing,and the traditional radio frequency bands have become overcrowded.As a large number of unlicensed bands exist in the millimeter-wave band and have great potential in the field of wireless communications,millimeter-wave communication systems emerge as the times require.As an important part of this systems,the Voltage-controlled Oscillator(VCO)has gradually become one of the most important research subjects of scholars at home and abroad.In this thesis,the millimeter wave VCO has been studied,and the VCO circuit working in the frequency band of 140 and 220 GHz has been researched and designed.The main contents are as follows:First of all,the thesis introduces the attenuation of millimeter wave propagating in the atmosphere and the concept of "atmospheric window".Then it introduces the millimeter wave transceiver system and its application,summarizes the research status,circuit structure,design method,process and various performance indicators of millimeter wave VCO at home and abroad.Secondly,the basic principle of the oscillator is analyzed and some typical oscillator structures are given.At the same time,the important parameters of the VCO and some factors to be considered in the design are introduced,laying a theoretical foundation for the circuit design.The final design and implementation of the following VCO circuit:1.140 GHz band differential VCO.The VCO based on 0.45 um In P HEMT process,using a differential capacitor three-point structure,the design of the signal transmission line is microstrip line structure,the core transistors of the oscillator work under zero gate bias.Taking into account the deviation of process,the design reserved for the 5-8GHz oscillation frequency,the VCO's frequency range from 145.3GHz to 148 GHz.In this frequency range,the output power is greater than 0.1d Bm,up to 0.44 d Bm,the phase noise performance is good and reaches-97.1d Bc/Hz@1MHz at 147.8GHz.2.140 GHz band Colpitts VCO.The VCO is based on 1um In P HBT process,designed with a single-transistor architecture that delivers over 3d Bm of output power in the full frequency range,up to 4.1d Bm.The microstrip line with a ground shield achieves the signal transmission line in the circuit design,the VCO swing frequency of 138-141.8GHz,and has relatively good tuning linearity,the phase noise in the whole frequency band is about-80.5d Bc/Hz@1MHz or so.3.A common-base cross-coupled VCO with base feedback inductance in the 140 GHz band and an improved circuit using a transformer.The design is based on 1um In P HBT process using a common-base cross-coupled structure that is better suited for high-frequency oscillators.At the same time,the base feedback inductor is used to boost the value of the negative-resistance part of the oscillator and improve the start-up state.The VCO's oscillation frequency range from 137.4GHz to 141.2GHz,the output power of 1.5d Bm above,the phase noise in the full band is about-82 d Bc/Hz@1MHz or so.Then the passive transformer on the chip is designed and adopted to improve the circuit structure.The improved circuit uses two pairs of varactors to increase its frequency tuning range,eventually achieving a tuning range of 140-150.7GHz,the output power is greater than 2d Bm in most of the frequency range,and has better phase noise performance than the previous circuit,is about-87 d Bc/Hz@1MHz or so.4.220 GHz band coupling line VCO.The VCO is based on 1um In P HBT process.On the basis of the traditional push-push common-emitter cross-coupled oscillator,the coupling line is designed and used instead of the DC blocking capacitor and load inductor in the feedback path.The frequency is tuned by the base bias voltage VBE and the second harmonic output is taken.Finally,the oscillation frequency of 217-237 GHz is achieved,the output power is about-2.9d Bm,the phase noise performance in the whole frequency band is basically about-90 d Bc/Hz@1MHz,and has good tuning linearity.