A piezoelectric transducer‐tuned microstrip‐ring resonator oscillator operating at the second resonant mode of the ring resonator

A microstrip open‐loop resonator oscillator operating at even modes is proposed. The even mode of the ring circuit can be predicted by using a simple transmission‐line model. The new oscillator has a characteristic similar to that of a push‐push oscillator. In addition, in comparison with the push‐push oscillator, the new oscillator with one active device can minimize the size and lower the cost. A voltage‐controlled piezoelectric transducer (PET) is used to vary the resonant frequencies of the ring resonator, which in turn tunes the oscillator with a good tuning range of 4.9% at around 12.1 GHz. This tuned oscillator should have many applications in wireless systems. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

一种CMOS电流饥饿型环形压控振荡器

设计了一种基于CSMC的0.5μm工艺的电流饥饿型环形压控振荡器。仿真工具采用Cadence Spectre,仿真结果表明,振荡器相位噪声达到了-105.432dBc/Hz@1MHz。     

一种带电源电压和温度补偿的振荡器电路设计

设计了一个带电源电压补偿和温度补偿的低功耗环形振荡器电路,环形振荡器采用受限于PTAT电流的反相器和普通CMOS反相器级联结构。由于电源电压和温度对这两种反相器传播延时的影响是相反的,利用这种相反的特性使得振荡器输出频率在电源电压和温度特性上得到补偿。该电路采用0.18μm CMOS工艺,测试结果显示在5 V电源电压以及27℃温度条件下,输出频率为263 k Hz,平均电流消耗为2.5μA。在3.5 V~5.5 V电源电压和-40℃~85℃的温度变化范围内,输出频率偏差在-2.3%~6.5%范围内。     

Class G approach for low‐voltage,high‐efficiency PA design

Class G power amplifier (PA) design guidelines are presented and experimentally validated, showing the interesting features of the new approach. For the same operating conditions, the Class G amplifier exhibits superior performances if compared to a tuned load one in large signal gain, output power, and third‐order intermodulation (IM3), with a power‐added efficiency (PAE) improvement of 38.5%. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 366–378, 2000.     

新型方波-直流电压信号的转换方法

围绕CCD(电荷耦合器件 )线阵在控制电路中的应用的难点 (如何将CCD输出的原始信号经过初步处理后所得的方波信号转换成直流电压信号 )进行了讨论和分析。首先介绍了两种传统的转换方法 ,并对这两种方法的优缺点进行了分析和比较。最后提出了一种新颖的转换方法 :基于滤波思想的方波 -直流电压信号的转换方法。经实验验证 ,这种方法所得的直流电压信号确实稳定、可靠     

Highly efficient switched‐mode transmitter using a current mode class‐D RF amplifier

This article presents a switched‐mode transmitter architecture using a current mode class‐D (CMCD) amplifier. To achieve high average efficiency for a modulated signal the envelope of the complex baseband signal is transformed into pulses such that the CMCD amplifier is operated either at its peak efficiency or completely switched off. The CMCD amplifier has been designed based on single‐tone active harmonic load‐pull measurements to achieve a power‐added efficiency (PAE) of 61.5% with 25 W output power at 900 MHz using LDMOS FETs. Removing the losses of the demodulation filter and of the amplifier a 10% higher efficiency than in an ideal class‐B amplifier can be obtained for burst‐mode operation with a peak‐to‐average power ratio of 10 dB. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

A high‐aperture‐ratio and low‐crosstalk pixel structure design for in‐plane‐switching‐mode TFT‐LCDs

Abstract— The TFT‐LCD market is growing rapidly, and the replacement of CRT TV by LCD TV requires the implementation of LC modes with wide viewing angles and high brightness. The IPS mode is an excellent technology to realize wide viewing angles, but it has a low aperture ratio that has now been improved by Advanced Super‐IPS (AS‐IPS). In this paper, we propose a novel pixel structure design that not only increases the aperture ratio but also reduces the crosstalk. We have improved the current AS‐IPS aperture ratio by 1.25 times and effectively reduced the capacitive coupling ratio from 1.2% to 0.05%.     

A low power and small area all digital delay-locked loop based on ring oscillator architecture

A 133-500 MHz,5.2 mW @500 MHz,0.021 mm2 all digital delay-locked loop(ADDLL)is presented.The power and area reduction of the proposed ADDLL are achieved by implementing a high frequency ring oscillator(ROSC)to count the reference clocks such that the one-clock cycle delay chain and the phase detector in a conventional Master block are no longer needed.The proposed ADDLL has better immunity to PVT(process,voltage,and temperature)than most conventional DLLs,which do not update the control word signals after the locking process,since the control signals for slave delay line are updated in every 256 reference cycles.Fabricated in 0.13 um CMOS process,the measured RMS jitter is 10.83 ps at 500 MHz while the RMS jitter of the input signal is 9.97 ps.     

Substrate‐integrated waveguide band pass filters with frequency‐dependent coupling elements

An effective technique to improve the stop‐band frequency response of direct‐coupled resonators in substrate‐integrated waveguide (SIW) technology is introduced. Regular inductive‐iris filters in SIW technology are supplemented with H‐plane frequency‐dependent inverters which not only create transmission zeros but also serve as the proper impedance inverter. A synthesis technique is introduced to prescribe transmission zeros at finite frequencies on either side of the pass band, symmetrically or asymmetrically. Two different topologies of frequency‐dependent inverters for X‐band SIW band pass filters demonstrate that attenuation poles can be created on both side of the passband and significantly improve the filters' stop‐band performences. Measurements confirm the validity of the presented design approach. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:237–242, 2014.     

Reflective full‐color LCD using low‐temperature polysilicon TFTs in low‐frequency driving: Analysis of image persistence and flicker with scientific CMOS camera

Image persistence and flicker are major issues for low‐frequency driving of LCDs. Detailed investigation of the mechanisms that produce these phenomena, using image analysis with a scientific CMOS camera, enabled us to reduce it to acceptable levels. We successfully developed a 7.0‐in. WUXGA (1200 × RGBW × 1920) reflective color LCD driven by low‐temperature polysilicon TFTs at 1 Hz.     

一种新的陀螺振子及工作方式的研究

本文提出了一种新形式的陀螺振子结构,介绍了其工作原理。当陀螺振子在驱动模态谐振时,检测与驱动正交振动位置的振动情况,推导出了两模态振动公式。利用有限元软件建模,对新振子能否满足驱动与检测模态频率相等的灵敏度要求进行仿真验证。     

A reconfigurable DCS1800/W‐CDMA LNA: Design and implementation issues

The authors present in this article a dual‐standard dual‐mode low‐noise amplifier (LNA) for DCS1800/W‐CDMA‐FDD applications. To save die area compared to conventional parallel LNAs, the authors have employed an alternative circuit configuration. It consists of sharing the most die consuming elements (inductances) in both operation standards, enabling a more compact solution. The standard selection is performed through a bias scheme (MOS switches) that allows alternating between the two involved standards. The LNA die area is 1.0 × 1.2 mm² and it consumes 6.8 mW (3.8 mA under 1.8 V), including bias circuitry. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

A fast mode‐matching‐based analysis of lossy magnetron‐type cavity

A strategy of fast computer analysis of a magnetron‐type cavity is developed based on combination of rigorous mode‐matching formulation and its simplified versions. Numerical examples are given when varying the aperture opening of the grooves and the radius of the noncorrugated inner conductor, for TE‐modes corresponding to the first and second natural frequencies which are of most practical interest. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 202–212, 2000     

Toward The Implementation Of A Seek‐Controller For An Optical Pick‐Up Head Using A Discrete Sliding‐Mode Control Scheme

Chattering is inevitable in most sliding‐mode controllers due to finite and imperfect switching. Most of the discrete‐time sliding‐mode schemes reported to date fail to alleviate chattering effectively; even under perturbation‐free conditions, chattering is still inevitable. This present work proposes a scheme that can guarantee both one‐sided behavior and chattering‐free performance with uncertainties of the known bounds of the plant. This scheme is applied to the design of a seek‐controller for an optical pick‐up head to illustrate its feasibility. Both simulation and experimental studies were performed to further validate its effectiveness.     

Quasi‐Time‐Dependent Controller for Discrete‐Time Switched Linear Systems With Mode‐Dependent Average Dwell‐Time

This paper is concerned with the stability and stabilization problem of a class of discrete‐time switched systems with mode‐dependent average dwell time (MDADT). A novel Lyapunov function, which is both mode‐dependent (MD) and quasi‐time‐dependent (QTD), is established. The new established Lyapunov function is allowed to increase at some certain time instants. A QTD controller is designed such that the system is globally uniformly asymptotically stable (GUAS) and has a guaranteed performance index. The new QTD robust controller designed in this paper is less conservative than the mode independent one which is frequently considered in literatures. Finally, a numerical example and a practical example are provided to illustrate the effectiveness of the developed results.      

Intelligent Integral Backstepping Sliding‐mode Control Using Recurrent Neural Network For Piezo‐flexural Nanopositioning Stage

In this study, an intelligent integral backstepping sliding‐mode control (IIBSMC) system using a recurrent neural network (RNN) is proposed for the three‐dimensional motion control of a piezo‐flexural nanopositioning stage (PFNS). First, the dynamic model of the PFNS is derived. Then, an integral backstepping sliding‐mode control (IBSMC) system is proposed for the tracking of the reference contours. The steady‐state response of the control system can be improved effectively due to the addition of the integrator in the IBSMC. Moreover, to relax the requirements of the bound and discard the switching function in the IBSMC, an IIBSMC system using an RNN estimator is proposed to improve the control performance and the robustness of the PFNS. The RNN estimator is proposed to estimate the lumped uncertainty, including the system parameters and external disturbance, online. Furthermore, the online tuning law for the training of the parameters of the RNN is derived using the Lyapunov stability theorem. In addition, a robust compensator is proposed to confront the minimum reconstructed error occurring in the IIBSMC system. Finally, some experimental results for the tracking of various contours are given to demonstrate the validity of the proposed IIBSMC system. From the performance measurements of the proportional‐integral control, sliding mode control, IBSMC, and IIBSMC systems, the proposed IIBSMC system has the lowest maximum, average, and standard deviation of the position tracking errors for three‐dimensional motion control of the PFNS.