Research On Passive Components And Optimization Of Lc Vco

In the last decade wireless engineering has seen outstanding progress in the area of mobile phones, intelligent transport system and television feasible. The high demand market is a driving need for higher integration in the wireless transceivers. The trend is to achive low-cost, small form factor and low power consumption. With the help of the aggressive scaling-down of the minimum feature size in complementary metal oxide semiconductor (CMOS) technology, deep-submicron CMOS technology is now considered as the mainstream for high speed communications and radio-frequency (RF) applications.MIM capacitors are very important passive components in CMOS process, which is used in dc decoupling, biasing circuit, low noise amplifier (LNA) and oscillator. Substrate noise coupling effect often occurs in the mixed signal ICs, which seriously interferes the normal performance of the analog circuits. Some researcher aims at reducing signal injections into Si substrate. So the shield layer connected to ground is designed under the bottom plate of MIM capacitor.In this paper a MIM capacitor with concave shield structure is presented in 0.13μm CMOS process. Experiments are carried out to study the effects of concave shield on Q factor and main capacitance compared with unshielded MIM capacitor. Chip measurements reveal that the concave shield improves the quality factor by 11% at 11.8 GHz and 14% at 18.8 GHz compared with unshielded MIM capacitor. In addition, results of a conventional plane shield are compared to demonstrate the effectiveness of the concave shield structure in alleviating the parasitic capacitances. On-wafer testing technique and parameter extraction procedure are presented. Moreover, concave shield simplify substrate modeling. A simple circuit model of the MIM capacitor with concave shield is presented for RF application.A successful design with a high production yield is based on accurate modeling of all the components of the system. As the operation frequency of RF ICs steadily increases toward the 5 GHz regions and above, many RF IC designers urgently require that an RF device model should be as simple as possible with high accuracy over a wide frequency range. In this paper, a new circuit model for LTCC inductors is presented incorporating skin effect and proximity effects. The model fits very well with the data in various structures: meander line style inductor, spiral inductor and helical inductor. Since the proposed model consists of frequency-independent lumped elements, it can be easily implemented in simulation program with integrated circuit emphasis (SPICE)-compatible simulators.On-chip spiral inductors are widely used in RF integrated circuits (ICs) due to ease of process integration. They are important components in VLSI circuits, such as voltage-controlled oscillators (VCO), filters or low-noise amplifiers (LNA). In this paper we poposed a simple wideband circuit model for on-chip spiral inductors based on skin effect,proximity effects and loss of substrate. The model shows excellent agreement with measured data mostly within 4.91% across a variety of inductor geometries up to 20 GHz 0.13μm CMOS process. The proposed model has been verified with measured results of inductors fabricated in 0.13μm CMOS process. The inductors have two dimensions: turn and inner radius. The new model accurately captures series resistance and inductance over a wide frequency range, even beyond the self-resonant frequency.Based on the analysis of phase noise, we optimize the design of VCO. And we analyse the application of passive components in LC VCO. A MIM capacitor is designed based on Process Design Kit. Compared the MIM capacitor in PDK, the area of new MIM capacitor has obvious decrease. The new MIM capacitor is used in VCO design .And we compare the effect on the performance (frequency and phase noise) in 0.18μm CMOS process.We study the effect of buffer on performance of VCO when the frequncy division is designed to generate quadrature signal.These two motheds has verified in frequency synthesizer in 0.18μm CMOS process.