A technique for truly linear LC VCO tuning, a proof of concept

Based on the understanding of the relation between the shape of the LC VCO tuning curve and the varactor characteristics, a technique using an array of unequal varactors with different bias was found to obtain a truly linear tuning curve. An LC VCO was designed using TSMC 0.13 μm 1.2 V/3.3 V IO process, the VCO frequency varies from 1.9 to 2.7 ghz as its control voltage varies from 0 to 1.2 V. The tuning gain was K_VCO=630 MHz/V ±9.5%.     

微波非线性电路全频域谐波平衡分析

本文提出了有关全频域谐波平衡方程的牛顿－拉夫逊迭代求解的一种改进方法。     

压控振荡器相位噪声、功耗和频率调谐特性的设计优化

To meet the requirements of the low power Zigbee system, VCO design optimizations of phase noise, power consumption and frequency tuning are discussed in this paper. Both flicker noise of tail bias transistors and up-conversion of flicker noise from cross-coupled pair are reduced by improved self-switched biasing technology, leading to low close-in phase noise. Low power is achieved by low supply voltage and triode region biasing. To linearly tune the frequency and get constant gain, distributed varactor structure is adopted. The proposed VCO is fabricated in SMIC 0.18-μm CMOS process. The measured linear tuning range is from 2.38 to 2.61 GHz. The oscillator exhibits low phase noise of -77.5 dBc/Hz and -122.8 dBc/Hz at 10 kHz and 1 MHz offset, respectively, at 2.55 GHz oscillation frequency while dissipating 2.7 mA from 1.2 V supply voltage, which well meet design specifications.     

微波非线性电路稳态响应分析的理论与算法

本文建立了适于非线性微波电路ＣＡＡ与ＣＡＤ的谐波平衡算法，通过增广谐波平衡方程，微分线性化网络，非线性伴随网络等概念的引入，使得谐波平衡方程的求解和电路灵敏度的计算简捷，高效，概念清晰，且易于和已有的线性微波电路频域分析软件结合。提出了多级网络分析的松驰谐波平衡法，使得在一般的微机上可进行中等以下规模非线性微波电路的分析与设计。     

锁相环电路中压控振荡器的分析与设计

本文设计了一个应用于高频锁相环（PLL）系统的负阻LC压控振荡器,在传统LC压控振荡器基础上,通过采用二次谐波滤波技术降低了振荡器的相位噪声,并完成了电路的仿真。仿真结果表明,该压控振荡器的振荡频率在1．9—2．1GHz,其频率调节范围达到200MHz,并且在距中心频率1MHz处其相位噪声为-148．825dBc／Hz...     

非线性电路稳态分析中非线性函数的谱计算

谐波平衡法是非线性电路中稳态分析的一种有效的方法。作为这种方法的重要组成部分，时域和频域之间的变换与反变换需要反复地进行．因此，其算法的好坏，直接关系到谐波平衡法的效率，本文针对这一问题，提出一种新的计算非线性元件频谱的方法，根据非线性函数本身的性质，充分利用稳态响应中各频率分量已知等信息，直接获得非线性元件的响应，从而达到了快速、准确的目的。     

微波功率放大器非线性失真分析

功率放大器非线性失真产生的交调失真、邻道干扰等直接影响通信系统的性能，在放大器模型的基础上，如何定量地描述和分析其非线性具有重要意义。文中讨论了放大器非线性失真的泰勒级数分析法、Volterra级数分析法和谐波平衡分析法，给出相应的仿真和实验结果。结果表明：根据非线性的强弱采用不同的分析方法，结果具有较大的参考意义。     

THE LARGE-SIGNAL DESIGN FOR FET FUNDAMENTAL AND HARMONIC OSCILLATORS

A Large-signal model for GaAs FET is derived based on its small-signal S parame-ters and DC characteristics. The harmonic balance algorithm is applied to analyze and optimizethe FET fundamental and harmonic oscillators, and the values of steady current are obtained.In the solving process, a simplified CAD approach is used to obtain the parameters of matchingnetwork when the output power is maximum. Finally, a fundamental oscillator and a harmonicoscillator of Q-band are fabricated. The measurements show that the theoretical analysis andexperimental results are in good agreement.     

A wide band differentially switch-tuned CMOS monolithic quadrature VCO with a low Kvco and high linearity

A wide band, differentially switch-tuned CMOS monolithic LC-VCO is presented in this paper, as well as a frequency divider for high linearity, low Kvco quadrature signal generation. A linearity control logic is proposed. The Kvco linearity is improved to be lower than 17.68 MHz/V. By using the proposed CML DFF, the operating frequency of the frequency divider is increased by 20% with a power consumption of 3.6 mW. The proposed design has been fabricated and verified in a 0.18 μm CMOS process. The QVCO is tuned in a combined way of continuous technology and 4 bit binary switch capacitor array (SCA) discrete tuning technology. The measurement indicates that the QVCO has a 19.7% tuning range from 1.816 to 2.213 GHz. The measured phase noise is −112.25 dBc/Hz at 1 MHz offset from the 1.819 GHz carrier and draws a current of 4.0 mA around at a 1.8 V supply.     

毫米波上变频器的非线性分析

本文提出了一种新的多频大信号激励下非线性电路计算方法——伪混叠法。它在谐波平衡法的基础上,利用频谱间的间隙,大大降低了采样率,并且推导出了叠代时所用的雅可比矩阵的解析表达式,从而提高了计算速度和精度。利用以上算法计算了Ka波段上变频器的输出特性,并和实测值进行了比较,其结果是令人满意的。     

S波段射频前端小型化的设计与实现

随着相控阵雷达技术的发展,射频前端作为T/R组件的核心器件,向高性能、高可靠、多功能、小型化及低成本趋势不断发展。本文使用GaN功率器件和微组装技术,结合几种关键器件小型化设计的方法,设计了S波段小型化射频前端。在6~8 dBm输入的条件下,发射通道输出功率达到200 W,效率达到50%以上;接收通道可实现30 dB的增益和1.5 dB噪声系数的设计指标。该技术已广泛用在射频相关产品中。     

用算术运算法分析多频率激励微波非线性电路

用全频域谐波平衡法的算术运算法分析多频率激励下电路的稳态响应，给出了一种新的Ｊａｃｏｂｉａｎ矩阵的构造方法，能分析任意多的频率激励情况。     

Ka波段双调谐VCO的分析和研制

本文分析了反射式腔稳双变容管调谐耿氏振荡器的调谐特性和相位噪声性能，研制出的Ka波段双调谐VCO的性能为：输出功率50－100mW，粗调谐10－20MHz/0-15V，细调谐±1－3MHz/0.-15V，相位噪声为－60dBc/Hz(fm=1KHz),-95dBc/Hz(fm=50KHz)。该双调谐VCO已成功地应用于某毫米波系统中。     

一种施密特触发器型压控振荡器的设计与仿真

传统施密特型压控振荡器存在输入电压下限值较高、最高振荡频率较低等缺点。针对这两个问题,文中介绍了一种具有新型充放电电路结构的施密特型压控振荡器,并在0.18 μm工艺下对电路进行了仿真。结果表明,相对于传统施密特型压控振荡器,新型振荡器输入电压下限值有所下降,且最高振荡频率也有明显提升。     

Analysis, design, and implementation of a random frequency PWMinverter

Random pulse width modulation (RPWM) approaches can make the harmonic spectrum of inverter output voltage be continuously distributed without affecting the fundamental frequency component, and thus the acoustic noise and mechanical vibration of an inverter-fed AC motor drive are greatly reduced. However, the analysis and design of the RPWM mechanisms are generally not so trivial for practical engineers that their applications are limited. In this paper, a random frequency PWM (RFPWM) inverter and its practical design procedure are presented. First, the effects of the attributes of a random signal on the inverter output harmonic spectrum distribution characteristics are analyzed using an intuitive concept, then based on which, the quantitative design. Simulink simulation and implementation of the proposed RFPWM inverter are introduced. The proposed RFPWM inverter is employed to power an indirect field-oriented induction motor drive. The simulated and measured results indicate that the uniform random distribution of inverter output harmonic spectrum and thus smaller acoustic noise and mechanical vibration are obtained by the proposed RFPWM scheme     

射频收发系统中VCO的分析与设计

针对目前通讯系统中数据高传输率和低误码率对于系统中各部分的较高要求,设计了一种采用谐波滤除电阻技术降低相位噪声和功耗的交叉耦合互补结构的VCO(压控振荡器).采用Chartered 0.35 μm CMOS工艺在Mentor Graphics Eldo-RF环境下对电路进行仿真设计,仿真结果表明此振荡器在1 mA工作电流下,在4.0 GHz处达到-118.4 dBc/Hz@1 MHz的相位噪声,功耗仅为1.83 mW,其性能满足当今射频通讯系统的基本要求.     

宽带低相噪CMOS LC VCO的设计

设计了一款宽带CMOSLCVCO,在分析VCO相位噪声来源的基础上,对VCO进行了结构优化和噪声滤除,并采用了开关电容阵列以增加带宽。电路采用0.18μmCMOS射频工艺进行流片验证,芯片面积为0.4mm×1mm。测试结果显示:芯片的工作频率为3.34～4.17GHz,中心频率为4.02GHz时输出功率是-9.11dBm,相位噪声为-120dBc/Hz@1MHz,在1.8V工作电压下的功耗为10mW。     

Reliability analysis of MOS varactor in CMOS LC VCO

The paper investigates the reliability of MOS varactor tuned voltage-controlled oscillators (VCO). Due to the stress induced threshold voltage shift of the MOS varactor, the resonant tank degrades and the center frequency and phase noise of VCO deviate. The behavior is modeled and an adaptive body biasing scheme is proposed to make VCO resilient to reliability. In the mean time it does not degrade the VCO performance. An LC VCO at 24 GHz carrier frequency with adaptive body biasing is compared with VCO without such biasing design in PTM 65 nm technology. The ADS simulation results show that the biasing design helps improve the robustness of the VCO in resonant frequency. The design reduces the frequency sensitivity of VCO by 20% when subjected to threshold voltage degradation.     

宽带VCO自动幅度控制电路中检幅电路的设计

设计了一种新型的幅度检测器用于宽带CMOSVCO的自动幅度控制电路中,通过AAC确保了VCO在整个带宽内能够可靠的起振,同时,新的幅度检测器解决了传统幅度检测电路导致的VCO相位噪声恶化的问题。基于Chartered0.25μm CMOS工艺的测试结果表明,在AAC电路运用新型的检幅电路后,VCO在全波段能够可靠起振同时获得较好的相位噪声特性,偏移中心频率10k处的相噪能改善6dBc。