A compact dual‐band crossover using coplanar‐waveguide‐fed dual‐mode ring resonators

In this article, a compact dual‐band crossover using dual‐mode ring resonators by Coplanar‐Waveguide (CPW)‐Fed scheme is proposed. It contains 2 homocentric square ring resonators on the top layer to obtain the dual‐band responses. CPW feeding lines and open stubs are placed on the bottom layer to feed the ring resonators and adjust coupled strength. The center frequencies and bandwidths for each passband can be individually controlled easily. To prove the design concept, a compact dual‐band crossover operated at 1.57 and 2.45 GHz is designed and fabricated. The measured results show good agreement with the simulation ones results a wide frequency range.     

一种新的基于正交实验设计的约束优化进化算法

提出了一种新的基于正交实验设计的约束优化进化算法.新算法的主要特点是:在搜索机制方面,利用正交实验设计方法安排多个父代个体的交叉操作,提出了一种新的多父体正交交叉算子,新的交叉算子能够有效利用多个父代个体所携带的信息产生新的具有代表性的子代个体.此外,利用单形交叉算子对父代种群进行并行搜索,以协调算法的勘探和开采能力.在约束处理技术上,新算法引入了一个衡量个体优、劣的新比较准则.通过13个标准的测试函数验证了算法的通用性和有效性.     

Digital‐to‐analog converter with gamma correction on glass substrate for TFT‐panel applications

Abstract— Low‐temperature polysilicon (LTPS) technology has a tendency towards integrating all circuits on glass substrate. However, the poly‐Si TFTs suffered poor uniformity with large variations in the device characteristics due to a narrow laser process window for producing large‐grained poly‐Si TFTs. The device variation is a serious problem for circuit realization on the LCD panel, so how to design reliable on‐panel circuits is a challenge for system‐on‐panel (SOP) applications. In this work, a 6‐bit R‐string digital‐to‐analog converter (DAC) with gamma correction on glass substrate for TFT‐panel applications is proposed. The proposed circuit, which is composed of a folded R‐string circuit, a segmented digital decoder, and reordering of the decoding circuit, has been designed and fabricated in a 3‐μm LTPS technology. The area of the new proposed DAC circuit is effectively reduced to about one‐sixth compared to that of the conventional circuit for the same LTPS process.     

基于结构矩阵的电路网表编码方法的研究

在模拟电路演化领域,电路知识表示是首要解决的问题。网表编码操作简单,对于拓扑结构没有限制,但是网表编码会在种群初始化和遗传操作过程中产生大量的非法电路个体。为解决这一问题,提出结构矩阵,并总结出合法电路结构矩阵所具有的性质,以结构矩阵为规范设计出合适的种群初始化步骤和能够用于网表编码的结构交叉算子,通过演化来验证效果,实验结果显示该方法能够较好地解决网表编码所存在的问题。     

求解旅行商问题的一个改进的遗传算法

利用遗传算法求解TSP问题,通常需要使用PCX,CX和OX等特殊的交叉算子以提高算法的运行效率。针对自然数编码的方式,提出一种改进的遗传算法,即改进传统的顺序交叉算子,进行不相同子排列顺序交叉,使子代继承父代中优秀的子排列,加快算法的收敛速度。另外,采用没有重复的稳态繁殖避免早熟。实验结果表明,此改进算法对于TSP和DHC问题均具有较好的性能。     

基于动态维度交叉的粒子群高维函数优化

提出一种优化高维函数的改进粒子群算法.粒子群算法在高维函数优化方面精度比较低,种群容易陷入停滞,分析粒子群算法在针对高维函数方面难以优化的原因,提出一种基于动态维度交又的改进粒子群算法,通过对五个典型测试函数的仿真,说明该算法具有摆脱较快的收敛能力和较高的收敛精度.     

Handling variable string lengths in GA-based structural topology optimization

Binary coded genetic algorithms (GAs) have been used effectively in topological design of discrete structural systems. In a majority of such applications, the structural topology is extracted from a pre-defined structural universe, a set of all permissible joints and elements that can be used in the development of the optimal design. In the presence of a dense structural universe, the GA search process must contend with very long string lengths, with the attendant degradation in the effectiveness of the search process. The present paper presents a novel approach for handling variable string lengths in GA-based topological design. Varying string lengths in a population requires a redefinition of the crossover process, and both inter- and intra-species crossover mechanisms are explored in the present paper. The use of micro-GAs is proposed as an approach to increasing the search efficiency in problems involving a large number of candidate topologies. The proposed strategies are implemented in representative algebraic problems, truss topology design, and the layout of a stiffened composite panel.     

基于Mealy机精化关系的验证算法

与传统验证方法相比,形式验证技术因其完备性,已在数字电路设计领域中得到越来越多的关注。通过对形式验证技术和状态机的研究,在LTL公式的可实现策略基础上,提出一个基于Mealy机精化关系的验证算法,实现了一个搜索工具原型:支持算术表达式的LTL性质描述,在设计空间中搜索满足给定规范的输入输出信号。该技术可应用于定位电路设计中满足给定功能性质的代码片段。     

A BTB UWB power divider with arbitrary power‐dividing ratio based on three‐slotline structure

In this article, a balanced‐to‐balanced (BTB) ultra‐wide band (UWB) power divider (PD) is proposed, which can realize arbitrary power‐dividing ratio (PDR) with improved transmission bandwidth flatness. The proposed PD is primarily based on microstrip/slotline (MS) transition structures and parallel‐coupled three‐slotline structure. U‐type microstrip feed lines integrated with stepped‐impedance slotline resonators are adopted at the input and output ports, which make the differential‐mode (DM) responses independent of the common‐mode (CM) ones. Meanwhile, superior DM transmission and CM suppression are achieved intrinsically, thereby simplifying the design procedure significantly. By changing the distances between the coupled three slotlines, the PDR between the output ports is controllable. In order to verify the feasibility of the proposed design method, several prototype circuits of the proposed PDs with different PDRs are simulated and a prototype circuit with the 2:1 PDR is fabricated and measured. A good agreement between the simulation and measurement results is observed.     

Direct synthesis of compact wideband differential bandpass filter on composite triple‐mode resonator

In this paper, a direct synthesis approach is proposed for design of a compact wideband differential‐mode (DM) bandpass filter (BPF) on a composite triple‐mode resonator. By virtue of intrinsic common‐mode (CM) suppression in slotline portion, only the DM transmission performances need to be focused on in our design, so as to facilitate the design process. Consequently, a synthesis approach based on an equivalent simplified network is established to design this DM BPF, resulting to directly determine all the circuit element values. A wideband DM BPF is then designed to validate effectiveness of proposed synthesis method. Finally, two circuit prototypes have been designed, fabricated, and measured. The synthesized, simulated and measured results agree well with each other over a wide operating band, which has demonstrated the proposed DM BPFs' attractive performances, such as wide bandwidth of operation, sharpened frequency selectivity, and good CM suppression.     

An iterative algorithm for maximizing robust performance in loop‐shaping design

In this paper, an algorithm that gives the best achievable performance bound on a given control problem is proposed using the loop‐shaping design framework. In view of standard design requirements, the robust performance is maximized at low and high frequencies while keeping the robust stability margin above a specified level, and the robust stability margin is directly improved at mid frequencies (around crossover). The proposed frequency‐dependent optimization problem is cast in an LMI framework. The resulting solution algorithm simultaneously synthesizes loop‐shaping weights and a stabilizing controller that achieve the maximum performance for a given level of robust stability margin corresponding to sufficient gain and phase margins of the closed‐loop system. Copyright © 2012 John Wiley & Sons, Ltd.     

New pixel driving circuit using self‐discharging compensation method for high‐resolution OLED micro displays on a silicon backplane

A new 4T2C pixel circuit formed on a silicon substrate is proposed to realize a high‐resolution 7.8‐μm pixel pitch AMOLED microdisplay. In order to achieve high luminance uniformity, the pixel circuit compensates its Vth variation of the MOSFET for the driving transistor internally by using self‐discharging method. Also presented are 0.5‐in Quad‐VGA and 1.25‐in wide Quad‐XGA microdisplays with the proposed pixel circuit.     

A novel symmetrical Wilkinson power divider for dual‐band application

A symmetrical two‐way Wilkinson power divider with shifted output ports, much wide bandwidth and large frequency‐ratio is proposed for dual‐band application. The corresponding transcendental design equations are derived by using the even‐ and odd‐mode analysis. Moreover, the closed‐form scattering parameter expressions are derived. Transcendental design equations are solved and accurate numerical design parameters along with different frequency ratios are obtained. Finally, the proposed structure and design method are validated by simulated and experimental results of typical microstrip planar power dividers, the performance is clearly observed for the input and output matching, isolation and transmission characteristic very well at the two band frequencies. More specifically, the measured transmission characteristics of the divider are 3.11 dB/3.58 dB at the 1.0 GHz/3.5 GHz, respectively. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:102–108, 2014.     

基于模式组合的粒子群优化测试用例生成方法

适应度函数的设计在基于搜索的测试用例生成技术中占据重要的位置,然而在某些特殊的程序中,如存在嵌套、非结构性跳转或因return,break等语句跳出循环的程序,已有的适应度函数无法评价到所有的分支.目前的方法是修改程序的源代码,以使每个分支得到评价.但修改源代码不但可能影响程序的原有结构、引入错误,而且很难实现自动化.针对这一问题,提出一种基于模式组合的粒子群优化测试用例生成方法.首先,将分支条件定义为"模式",即,一类具有相同特征且能提高适应度值的个体集合,并改变其分支函数的插桩方式,可解决分支条件不完全评价的问题;然后,设计一种新的交叉算子,寻找到所有使模式的分支函数值最小的个体,将这些个体中含有模式的部分通过交叉算子组合到一个个体上,既可防止模式在进化过程中被破坏,又可因多种模式的组合而提高个体的适应度值;最后,使用局部搜索策略对种群中的最优个体进行搜索,提高粒子群优化算法的局部搜索精度,进一步提高测试用例生成效率.为了评价该方法的有效性,基于一组基准程序和开源程序进行实验.实验结果表明:对于含有模式的程序,该测试用例生成方法与已有方法相比,在覆盖率和平均进化代数上均有明显优势.     

Dual‐feed full‐metal‐case antenna for WWAN/LTE smartphone applications

A dual‐feed small size full‐metal‐case (FMC) antenna for hepta‐band LTE/WWAN operation in smartphone applications is presented. The antenna proposed here is an integrated part of the full metal case located at the top edge of the smartphone, and it only occupies a small volume of 5 mm × 70 mm × 6 mm. It has two feeding ports that are separately connected to an ON/OFF switch (SW1 and SW2) for controlling the lower and higher operation bands, respectively. For the case when SW1 (ON) and SW2 (OFF), Port‐1 is engaged, and a lower operating band that covers the GSM850/900 operation (824–960 MHz) is achieved. In contrast, Port‐2 will be engaged for the case when SW1 (OFF) and SW2 (ON), and with the aid of a wideband matching circuit, the antenna can induce a higher operating band that can cover the DCS/PCS/UMTS2100/LTE2300/LTE2500 operations (1690–2690 MHz). Detailed design considerations of the proposed FMC antenna are described, and both experimental and simulation results are also presented and discussed. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:595–601, 2016.     

Compact planar frequency reconfigurable multiple‐input‐multiple‐output antenna with pattern and polarization diversity characteristics for WiFi and WiMAX standards

A compact planar frequency reconfigurable dual‐band multiple‐input‐multiple‐output (MIMO) antenna with high isolation and pattern/polarization diversity characteristics is presented in this article for WiFi and WiMAX standards. The MIMO configuration incorporates two symmetrically placed identical antenna elements and covers overall size of 24 mm × 24 mm × 0.762 mm. Reconfiguration of each antenna element is achieved by using a PIN diode which allows antennas to switch from state‐1 (2.3‐2.4 GHz and 4.6‐5.5 GHz) to state‐2 (3.3‐3.5 GHz and 4.6‐5.5 GHz). In state‐1, the configuration offers isolation ≥18 dB and 20 dB in lower band (LB) and upper band (UB) respectively; whereas, in state‐2, isolation ≥21 dB and 20 dB in LB and UB respectively is achieved. The same decoupling circuit provides high isolation in dual‐band of two states, which makes overall size of the proposed design further compact. The antennas are characterized in terms of envelope correlation coefficient, radiation pattern, gain, and efficiency. From measured and simulated results, it is verified that the proposed frequency reconfigurable dual‐band multi‐standard MIMO antenna design shows desirable performance in both operating bands of each state and compact size of the design makes it suitable for small form factor devices used in future wireless communication systems.     

Compact cell topology selection for size‐reduction‐oriented design of microstrip rat‐race couplers

In this work, we address the problem of compact cell topology selection for miniaturization of rat‐race couplers. The principal objective of the design process is to achieve the smallest possible footprint of the coupler, while maintaining the required levels of electrical parameters imposed on its components. Our approach permits identification of the minimum achievable coupler area, provided that the circuit is composed of a given compact cell and folded lines. This allows for the quantitative assessment of a set of considered cells with respect to the miniaturization capabilities they exhibit under certain design specifications. The proposed method is validated using 6 different cells with unified parameterization to identify the smallest rectangular‐like rat‐race coupler described by 2 design specifications. The obtained results attest that circuit topology and electrical parameters of the reference design are critical factors determining the final miniaturization rate. The proof‐of‐concept prototype devices occupy merely 8% of the conventional coupler area, while preserving fractional bandwidths (20% and 13.5%) of their conventional counterparts. The experimental results confirm the claims inferred from the numerical data.     

基于单形正交实验设计的差分演化算法

为了克服传统差分演化(DE)算法在求解约束优化问题时出现的收敛性慢和容易陷入早熟等缺陷,提出一种新的基于单形正交实验设计的差分演化(SO-DE)算法。该算法设计了一种结合单形交叉和正交实验设计的混合交叉算子来提高差分演化算法的搜索能力;同时采用了一种改进的个体优劣比较准则对种群个体进行比较和选择。这种新的混合交叉算子利用多个父代个体进行单形交叉产生多个子代个体,从两者中选择优秀个体进行正交实验设计得到下一代种群个体。改进的个体优劣比较准则对不同状态下的种群采用不同的处理方案,其目的在于能够有效地权衡目标函数值和约束违反量之间的关系,从而选择优秀个体进入下一代种群。通过对13个标准测试函数和2个工程设计问题进行仿真实验,实验结果表明SO-DE算法求解的精度和标准方差都要优于HEAA算法和COEA/OED算法。SO-DE算法具有更高的精度以及更好的稳定性。     

Analysis of scalable two‐π equivalent‐circuit model for on‐chip spiral inductors

High‐accuracy inductor model is vital for the success of RF/mm‐wave circuit design. In this article, the development of two‐π scalable model with four ladder skin effect structure has been described in detail. For the scalable compact circuit modeling, a set of formulas by which all of the compact circuit elements can be calculated according to the components geometric dimensions and process parameters will be given. The proposed modeling method is regarded as full scalable as all the component parameters are calculated by physical equations or revise equations. A series of spiral inductors with various geometries have been fabricated with 0.13 μm SiGe BiCMOS aluminum process to verify the model. Excellent agreements are obtained between the measured data and calculation form the proposed model up to frequencies above self‐resonant. This scalable 28‐element two‐π model enables to accurately characterize RF behaviors of on‐chip spiral inductors and optimize the inductor performance. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:93–100, 2015.     

科技触摸时尚——电子产品中的跨界设计浅析

时尚品牌与电子产品的融合设计是时下设计界的热门话题。本文着眼于当前诸多跨界的产品设计案例,从品牌、造型、用户体验等角度分析了跨界设计(crossover design)在电子产品设计中的应用手段,探讨了跨界设计在电子产品中的应用法则以及跨界设计的发展趋势。