Reseach And Chip Design Of Micro-wave And Millimeter-wave VCO Based On CMOS Technology

Phase-locked Loop(PLL)frequency synthesis directly affects the performance of wireless transceivers and is the key bottleneck to realize the full integration of a wireless transceiver.In a PLL,the VCO(Voltage Control Oscillator)provides the actual output signal and its performance directly determines the most of the performance parameters of the PLL.In addition,the PLL frequency spectrum purity also depends on the design of the VCO and inhibiting ability of the common mode noise modulation to the carrier frequency.Moreover,the VCO power consumption is accounted for most of the PLL power budget.Therefore,the study of the VCO design has an important significance.In this paper,with the support of Chinese 973-project,the research and chip design of microwave and millimeterwave(mmw)VCO based on CMOS tchnology is presented.The Ka band mmw LC-VCO circuit structure and the optimization methods will be mainly discussed.Two kinds of VCO circuits and the measurement results are given.A 3-7 GHz ultra-wideband VCO circuit is designed and the test results are given.As one of the LC-VCO passive components,an inductor is also designed and optimized.Octagon inductors are the common choice in CMOS technology,Better circular inductors will need to design and layout simulation by oneself.In this paper,a novel optimization technique is intruduced to investigate effects of the core diameter,metallization spacing,and the width on the performance of integrated spiral inductors.A dual-band,wide tuning range VCO that uses transformer-based 4th-order LC resonator with a compact common-centric layout is presented.Compared with the traditional wideband VCO,the frequency tuning range is doubled without degrading phase noise performance.The relation between the coupling coefficient of the transformer,selection of frequency bands,and the quality factor at each band is investigated.The transformer used in the resonator has a circular asymmetric concentric topology.Compared with conventional octagon spirals,the proposed transformer results in a higher quality-factor,and hence a lower oscillator phase noise.The VCO is designed and fabricated in a 0.18-?m CMOS technology and has 75%wide tuning range of 3.16?7.01 GHz.Depending on the oscillation frequency,the VCO current consumption is adjusted from 4.9 to 6.3 mA.The measured phase noises at 1 MHz offset from carrier frequencies of 3.1,4.5,5.1,and 6.6 GHz are?122.5,?113.3,?110.1,and?116.8 dBc/Hz,respectively.The chip area,including the pads,is 1.2 mm×0.62 mm and the supply voltage is 1.8 VThe principle and the topological structure of the VCOs in the mmw band are analyzed in detail in this paper.Since the Q-factor of the varactor decreases rapidly at mmw frequencies,the Q-factor of the varactor becomes the dominant factor which affects the phase noise rather than the inductor.The varactor of enhanced Q-factor at mmw frequencies are analyzed and applied to optimize the proposed VCO design.Moreover,an NMOS-only cross-coupled transistor pair is adopted to provide the negative resistance,and to minimize the parasitic capacitance and its impact on the phase noise.Fabricated in a standard 90-nm CMOS process,the proposed VCO achieves a wide tuning range from 33 to 40.2 GHz and a low phase noise of-103.4 dBc/Hz at 1-MHz offset.The power of the core circuit is 13.8 mW.The chip area is 0.53 mm×0.47mm.A low-power VCO with a wide tuning range and low phase noise has been designed and realized in a standard 90-nm CMOS technology.A newly proposed current-reuse cross-connected pair is utilized as a negative conductance generator to compensate the energy loss of the resonator.The supply current is reduced by half compared to that of the conventional LC-VCO.An improved inversion-mode MOS(IMOS)varactor is introduced to extend the capacitance tuning range from 32.8%to 65%.A detailed analysis of the proposed varactor is provided.The VCO achieves a tuning range of 27?32.5 GHz,a frequency tuning range(FTR)of 18.4%,a phase noise of-101.38 dBc/Hz at 1-MHz offset from 30-GHz carrier,and showed an excellent FOM of-185 dBc/Hz.With the voltage supply of 1.5 V,the power consumption of core circuit is only 3.7 mW.The chip area is 0.53 mm× 0.46mm.