IEEE 802.22授权频带多周期循环检测性能分析

认知无线电使用动态频率接入,应具备自动检测无线电频谱空洞功能。基于多周期循环检测算法,研究了IEEE802.22WRAN授权用户频带的特征感知方案。其基本思想是利用周期平稳信号的自相关函数以及协方差函数特性,计算自相关值的协方差,比较估计值与门限值,判决原信号是否具有循环平稳性,从而识别出各种信号类型。仿真利用两类授权用户信号特点进行精细感知,并着重分析了循环周期长度和延时等参数对检测性能的影响。结果表明增加计算自相关函数时的循环周期长度或采样点数,降低延时,都有利于信号检测,从而验证了该算法的优良性。     

基于砷化镓工艺的集成式功分器

A compact lumped integrated power divider with low insertion loss using 0.5 μm GaAs pHEMT technology is presented. The proposed power divider uses the π-type LC network for transmission line equivalence and a thin film resistor for isolation tuning simultaneously. The quality factor of the inductor is analyzed and synthesized for insertion-loss influence. The measured insertion loss is less than 0.5 dB when the operating frequency is within the range of 5.15-6.15 GHz. The return loss and isolation are better than 15 dB and 20 dB, respectively. The compact dimension of the power divider is as small as 0.9 × 0.85 mm^2. The measured results agree well with the simulated ones.     

Effect of electric field polarity on inter-poly dielectric during cell operation for the retention characteristics

Retention characteristic represents a capability to maintain the storage data and it is related with the reliability of memory device. The retention characteristic is degraded by the leakage of charges from a floating gate to a control gate, and thus the leakage current at low and moderate electric field of inter-poly dielectric (IPD) is one of the important characteristic for floating gate type flash memories. In addition, it is necessary to investigate the effects of the electric field polarity on the electric characteristics of IPD because the electric field polarity is changed as the cell operations such as the programming and erasing. Therefore, in this paper, the variation of the leakage current of IPD at moderate electric field region is measured with varying the previously applied electric field polarity. Based on the result, the effect of sequential change of an applied electric field polarity on the electrical characteristics is analyzed.     

基于高阻硅的毫米波IPD 滤波器研究

5G 通信迫切需要毫米波集成无源器件(Integrated Passive Device,IPD),要求该类器件低成本、高性能。基于高阻硅(High Resistivity Silicon, HRS)工艺设计并加工了一款四阶交叉耦合毫米波微带滤波器,基于测试结果和有耗耦合矩阵理论反提取得到四阶滤波器谐振器的真实无载品质因素。进而对高阻硅基的毫米波工艺参数(例如,损耗角正切)进行修正,利用电磁仿真软件进行验证;分析了金属粗糙度对于滤波器损耗的影响。修正后的模型仿真结果和测试结果吻合较好,验证了修正后毫米波段高阻硅基参数的有效性,为芯片级毫米波无源器件的设计提供了支撑。     

Catia aided radome analysis using geometric optics method

In this paper, the Geometric Optics (GO) method using the approximate ray paths coupled with the Computer Aided Tri-dimensional Interface Application (CATIA) meshing modeling are implemented to analyze the performance of electric large three-dimensional dielectric radome-enclosed antenna of arbitrary contour shape. The surfaces of the radome are approximated by planar triangular patches, the influences of various number of patches on power transmission coefficient and Insertion Phase Delay (IPD) via an ogive and a conical radome are discussed by the hybrid method. The simulation results indicate that computational error from planar triangular patches can limit in one percent, meeting the engineering application requirements.     

一种IPD吸收式低通滤波器的设计

为解决反射信号损害系统性能的问题,提出了一种具有高带外抑制和高带外吸收的小型化吸收式低通滤波器。该滤波器通过高通通路和低通通路实现了吸收式低通滤波器;通过抑制增益支路实现了高带外抑制。利用ADS和HFSS仿真软件对滤波器结构进行优化设计,并进行了实物的加工和测试。实测结果表明:该滤波器的3 dB截止频率为4 GHz,其带内最小插入损耗0.88 dB,通带内DC到3.5 GHz的回波损耗大于20 dB,阻带回波损耗大于10 dB,10.5 GHz处的阻带抑制大于45dB,从8 GHz到30 GHz的带外抑制大于33 dB,实测结果与仿真结果有较好的吻合。该滤波器尺寸仅为1220μm×650μm×87.71μm,相比传统PCB、LTCC工艺的滤波器,体积大大缩小,符合现代射频与微波系统小型化的发展趋势。     

Impact of substrate resistance and layout on passivation etch-induced wafer arcing and reliability

Wafer arcing, as a form of plasma-induced damage, occurs randomly, varies among different products and introduces problems into production yield and reliability. Conventional arcing theory is based on substrate conductive paths, for which the arcing frequency decreases as the substrate resistance increases. However, we observed the reverse result, i.e., silicon-on-insulator (SOI) and integrated passive device (IPD) wafers with high substrate resistance suffered a high frequency of passivation (PA) etch-induced arcing. In addition, the newly developed through silicon vias (TSV) interposer process for three-dimensional (3D) packaging also encountered a similar problem. To explain and solve these problems, we used substrates of different resistivities using the arcing-enhanced method to study this PA etch-induced wafer arcing phenomenon and revealed the mechanism underlying the effect of substrate resistance, the role of the seal ring, the root cause of the layout’s effect on arcing frequency and the impact on reliability. Next, we determined that the reduction in arcing relies on the simultaneous optimization of the process and the layout and observed that the reduction of the arcing source helps to improve product reliability. Finally, improvement methods and guidelines were proposed for both the process and the layout.     

系统集成中的高阻硅IPD技术

集成无源器件(IPD)技术可以将分立的无源器件集成在衬底内部,提高器件Q值及系统集成度。由于高阻硅衬底具有良好的射频特性,高阻硅IPD技术可以制备出Q值高达70以上的电感。高阻硅IPD基于薄膜技术具有高精度、高集成度等特点,可将无源器件特征尺寸缩小一个数量级。同时可利用成熟的硅工艺平台,便于批量生产降低成本。此外,高阻硅IPD技术可与硅通孔(TSV)技术兼容,可实现三维叠层封装。分析表明,高阻硅IPD技术在系统集成中具有广泛应用前景。     

硅/玻璃基板互连和无源元件的动向

概述了硅玻璃互连板和硅系集成无源元件(IPD)的动向。无源元件制造商的PCB嵌入用硅系芯片元件已经问世。硅基板上的微细薄膜线路和薄膜元件实现无硅化。     

SPECTRUM SHARING IN ITERATED PRISONER’ DILEMMA GAME BASED ON EVOLUTIONARY STRATEGIES FOR COGNITIVE RADIOS

We study a spectrum sharing problem where multiple systems coexist and interfere with each other. First, an analysis is proposed for distributed spectrum sharing based on Prisoners’ Dilemma (PD) in Cognitive Radios (CRs). In one-shot game, selfish and rational CRs greedily full spread their own spectrum space in order to maximize their own rates, which leads to Nash Equilibrium (N.E.). But with long term in-teraction, i.e., Iterated Prisoner’s Dilemma (IPD), CRs can come to cooperate and acquire the social optimal point by using different evolutionary strategies such as Tit For Tat (TFT), Generous TFT (GTFT), etc. Also we compare the performances of the different evolutionary strategies in noise-free and noisy environments for two-player games. Finally, N-player IPD (N-IPD) is simulated to verify our conclusions that TFT is a good strategy for spectrum sharing in CRs.