基于RBFNN和GA优化设计DGS微带*线

采用神经网络与遗传算法相结合的方法,对一种缺陷接地结构微带线进行优化设计。整个优化设计过程分为两步进行：首先采用基于混合递阶遗传算法优化训练的RBF神经网络对缺陷接地结构微带线进行建模,当神经网络模型训练成功后就实现了对这种缺陷地结构微带线传输系数快速和精确的输出仿真;然后利用该神经网络模型,并结合遗传算法共同优化设计这种缺陷地结构微带线的传输系数和尺寸参数。仿真结果验证了该方法的有效性和准确性。     

基于混合递阶遗传算法的判决反馈RBF网络信道均衡器设计

针对判决反馈RBF网络信道均衡器的结构特点,提出了一种混合递阶遗传算法,对网络隐层结构以及径向基函数中心和宽度采用递阶结构联合编码并分层次进行遗传操作,不仅可以确定隐层节点参数,同时也可以确定隐层节点数, 解决了网络拓扑结构的优化设计问题;将网络参数空间划分为线性空间和非线性空间分别进行优化训练,简化了递阶遗传操作空间,加速算法收敛。     

基于优化神经网络的三相全控整流电路故障诊断

研究了递阶遗传算法用于神经网络的参数确定问题,以期利用递阶遗传算法的二级编码结构解决以往同时优化神经网络结构、权值、阈值效率不高的难题。此外,建立了三相桥式全控整流电路的故障模型,并对几种常见故障进行了仿真分析。最后,将自适应递阶遗传算法用于三相桥式全控整流电路的故障诊断,仿真验证了该方法的准确性和实用性。     

基于径向基函数神经网络的混沌系统控制

考虑到不同神经网络模型误差对混沌控制效果的影响，提出了采用一种改进的递阶遗传算法对径向基函数（RBF）神经网络进行训练，针对连续的Lorenz系统进行了仿真，并且与其它神经网络训练算法结果进行了比较，仿真结果证明所采用的训练算法具有更加理想的混沌控制效果。     

小生境进化RBF网络在信道均衡中的应用

基于RBF网络的信道均衡器,其性能取决于神经网络的隐层参数.文中采用判决反馈均衡器的结构,RBF网络隐层的结构和参数则由基于小生境技术的混合递阶遗传算法来确定.仿真结果表明,这种RBF网络均衡器性能优良.     

基于递阶粒子群优化径向基函数人工神经网络的光性能监控

为解决差错反向传输神经网络在透明可重构光网络光性能监测中精度不足的问题,提出一种基于优化的径向基函数人工神经网络的光性能监测方案。在该方案中,以信号眼图参数为网络输入,以光信噪比、色散和偏振模色散为网络输出;采用二进制与十进制相结合编码的递阶粒子群方法,用适应度函数引导粒子向小规模和小误差方向运动,进行神经网络的结构与参数自适应优化;分别以不同光信噪比,不同色散和偏振模色散水平仿真信道中传输速率为40 Gb/s差分相移键控仿真信号,进行网络训练和测试,并将测试结果与相同情形下基于差错反向传输法神经网络的光性能监测结果进行比较。结果表明,所提方案在保有人工神经网络方案优点的基础上,有着更好的监测精度。     

基于自适应结构的径向基神经网络模式识别

为了提高神经网络模式识别的泛化能力,运用梯度下降、扩展卡尔曼滤波、无先导卡尔曼滤波和一种基于遗传算法与扩展卡尔曼滤波组合的新方法,对径向基神经网络的中心节点和权重进行了优化,建立了自适应结构的径向基神经网络模型,实现了对 IRIS 数据集的识别。通过仿真实验,对基于不同算法的径向基神经网络,从逼近能力、输出误差、学习效率与识别精确度等方面进行了分析比较。本文方法具有很强的非线性处理能力和自适应能力及较快的学习速度。     

基于遗传算法的BP神经网络在图像压缩中的应用

以神经网络和遗传算法为代表的进化算法都基于智能信息处理的理论,但是各自都存在一些缺陷.设计并实现了基于遗传算法的BP神经网络算法BP-GA,该算法将遗传算法和BP算法相结合,用基于实数编码的遗传算法优化神经网络的权值后,应用于图像压缩.实验证明,利用此混合神经网络进行图像压缩,压缩比高,图像恢复质量效果好.     

基于CMOS模拟电路的径向基函数神经网络

提出了可构成径向基函数(RBF)神经网络的CMOS模拟单元电路,包括绝对值电路、电流求均方根电路和类高斯函数电路.基于这些电路设计了一个二输入/一输出,含有两个隐层神经元的径向基函数神经网络,并通过异或问题进行了验证.所有单元均采用HJTC 0.18μm CMOS数模混合工艺制造,芯片面积为200μm×150μm,功耗约为100μW.芯片测试结果表明:提出的单元电路结构简单,功耗低,便于扩展和调节,因而为硬件实现径向基函数神经网络的片上学习提供了可     

基于CMOS模拟电路的径向基函数神经网络

提出了可构成径向基函数(RBF)神经网络的CMOS模拟单元电路,包括绝对值电路、电流求均方根电路和类高斯函数电路.基于这些电路设计了一个二输入/一输出,含有两个隐层神经元的径向基函数神经网络,并通过异或问题进行了验证.所有单元均采用HJTC 0.18μm CMOS数模混合工艺制造,芯片面积为200μm×150μm,功耗约为100μW.芯片测试结果表明:提出的单元电路结构简单,功耗低,便于扩展和调节,因而为硬件实现径向基函数神经网络的片上学习提供了可     

应用缺陷地结构设计低通滤波器

对缺陷地结构(DGS)实现的等效均匀传输线提出了一种简单有效的由S参数求其特性阻抗和有效相对介电常数的方法。而后比较了缺陷地结构和微带线的特性阻抗和有效介电常数随频率变化的规律。最后,应用缺陷地结构设计了两个Chebyshev低通滤波器,并进行了制作和测试。所得滤波器与采用微带线设计的相同参数的低通滤波器相比,阻带最大衰减有超过5dB的改善,并避免了实现高阻抗微带线的工艺困难。     

基于分形缺陷地结构的微带贴片天线

微带天线容易产生谐波和杂散波,造成天线性能的降低。将哑铃形缺陷地结构和分形缺陷地结构加入微带天线中,经过理论分析和实验测量,结果表明缺陷地结构不仅能够抑制天线的谐波和杂散波分量,还能抑制天线的交叉极化。与哑铃形缺陷地结构相比,分形缺陷地结构不仅能更好的提高微带天线性能,还能减少刻蚀接地板的面积,提高地板利用效率。     

Size reduction and harmonic suppression of rat-race hybrid coupler using defected ground structure

In this letter, a defected ground structure (DGS) is applied to design a compact microstrip rat-race hybrid coupler. The proposed structure can achieve both a significant reduction of size and harmonic signal. By embedding the DGS section, it is observed that the resonant frequency of the hybrid coupler is significantly lowered, which can lead to a large amount of size reduction for a fixed frequency operation. Besides, the third harmonic signal is suppressed to -30 dB with respect to a conventional rat-race hybrid coupler. In this case, the measured insertion loss is comparable to that of a conventional hybrid coupler.     

Support Vector Driven Genetic Algorithm for the Design of Circular Polarized Microstrip Antenna

In this paper, a hybrid soft computing method for designing specific microstrip antenna is presented. Evolutionary algorithm such as genetic algorithm (GA) is one of the promising ways of finding global optimum solution from a multivariate nonlinear feature space. Being a stochastic iterative algorithm, it requires much computation power when the function to be optimized is complex and time consuming. Various meta-modelling techniques such as neural network, response surface methods, kriging, etc. can be used to model the process under optimization in order to reduce the computational expenses. In this paper, we investigate one such technique – support vector regression (SVR) – to model the complex analytical process. The model, thus obtained, is used for optimization using genetic algorithms. This approach is demonstrated for the design of circular polarized microstrip antenna at 2.6 GHz band. The results of SVR model are compared with other meta-models generated with neural network and response surface methodology.     

A design of the low-pass filter using the novel microstrip defectedground structure

A new defected ground structure (DGS) for the microstrip line is proposed in this paper. The proposed DGS unit structure can provide the bandgap characteristic in some frequency bands with only one or more unit lattices. The equivalent circuit for the proposed defected ground unit structure is derived by means of three-dimensional field analysis methods. The equivalent-circuit parameters are extracted by using a simple circuit analysis method. By employing the extracted parameters and circuit analysis theory, the bandgap effect for the provided defected ground unit structure can be explained. By using the derived and extracted equivalent circuit and parameters, the low-pass filters are designed and implemented. The experimental results show excellent agreement with theoretical results and the validity of the modeling method for the proposed defected ground unit structure     

甚宽带PBG滤波器结构

研究了光子带隙结构作为微带电路衬底的情况,分析其阻带特性的形成以及对电路性能的影响.提出了利用级联与混合并联结构设计具有很宽频带的滤波器形式.实验测量了其传输特性,验证了频率阻带的存在和作为宽带滤波器结构的可行性.     

缺陷地结构在微带天线小型化中的应用

给出一种利用缺陷地结构实现天线小型化的方法,将缺陷地结构用于微带天线小型化的设计中,并对缺陷结构的尺寸与天线小型化的效果进行了分析。采用Ansoft HFSS进行仿真,在谐振频率为2.45 GHz的微带贴片天线的介质板上引入一种新型缺陷地结构,比较加入缺陷地结构前后天线的各项参数。其结果表明,该结构在保证天线性能的情况下,天线体积减小了30%以上。     

Ultra-wideband bandpass filter using hybrid quasi-lumped elements and defected ground structure

A compact planar microstrip ultra-wideband (UWB) bandpass filter is presented. The proposed UWB filter is realised by cascading a highpass filter (HPF) and a lowpass filter (LPF). Additional U-slot defected ground structure is adopted to improve the attenuation performance in the stop band. The HPF consists of inter-digital capacitors and a short-circuited stub. The LPF achieved by a hybrid microstrip and four backside slots on the ground plane is equivalent to a typical 9-pole stepped-impedance LPF. Combining these two structures, a new UWB bandpass filter is fabricated and measured. Measured results show that the proposed bandpass filter has a wide bandwidth from 3.1 to 11 GHz, and insertion loss is less than 1.2 dB over the most central passband. It also achieves a wide stop band with 20 dB attenuation up to 20 GHz.     

A novel defected ground structure for planar circuits

A new compact defected ground structure (DGS) is proposed for the microstrip line. The structure is compact in microstrip line direction. Here, this DGS is used to design a compact low pass filter (LPF) that is at least 26.3% more compact lengthwise than other reported compact structures and has sharper transition knee.