基于Simulink的PSWF求解算法仿真

针对现有椭圆球面波函数(PSWF)脉冲求解算法仿真效率低、直观性差等问题,从PSWF的微分方程定义出发,在Simulink环境中构建PSWF脉冲发生器,给出带通PSWF和具有陷波特性PSWF的脉冲设计方法,根据美国联邦通信委员会(FCC)频谱掩膜和抑制窄带干扰的要求分别产生PSWF脉冲,结果表明,该方法产生的脉冲能较好地满足FCC频谱掩膜要求,实现任意频点不同深度的陷波。     

一种宽带宽角双极化低剖面相控阵天线

提出了一种米波段的宽带宽角双极化相控阵天线,实现了结构简单、质量轻且剖面低的天线设计。辐射单元间的紧耦合提供了基本的宽带特性,对单支节巴伦的改进以及加载隔离板的措施则在降低剖面高度的同时进一步挖掘了宽带潜能;为改善宽角扫描性能,还引入了宽角阻抗匹配层。最终,在135 MHz ~270 MHz 仅0. 1λL 剖面高度内实现依45°扫描,在对低剖面要求严格的宽带宽角场合具有广泛应用前景。     

一种新的超宽带脉冲信号优化设计方法

从数值逼近理论出发按照Chebyshev最佳一致逼近准则将超宽带信号设计成符合FCC频谱模板的信号,与同类方法相比更容易控制设计精度,具有更高的频谱利用率,改善了UWB通信系统的性能,方法适用于不同的频谱模板.在理论分析的基础上对方法进行了阐述和模拟仿真,仿真结果验证了该超宽带脉冲信号设计方法的有效性.     

基于区域谷值双层EEMD方法的超宽带雷达生命信息检测

为解决心跳信息在低信噪比环境下难以提取的问题,提出一种基于区域谷值双层EEMD的信号检测方法。首先,对原始数据进行伪二维聚类经验模态分解(Pseudo Bi-Dimensional Ensemble Empirical Mode Decomposition,PBDEEMD)去除系统静态杂波以获得目标矩阵;其次,计算目标矩阵关于快时间轴的能量函数,选择能量函数上目标时间区域的谷值作为特征时间指数;最后,提取时间指数所对应的慢时间信号,并对信号进行聚类经验模态分解(Ensemble Empirical Mode Decomposition,EEMD)获得呼吸和心跳信息。仿真结果表明,在不同信噪比下,基于区域谷值的双层EEMD方法都可以实现呼吸与心跳信号的有效分离。     

A compact dual band-notched UWB circular monopole antenna with parasitic resonators

A compact dual band-notched Ultra-wideband (UWB) circular monopole antenna that has two parasitic resonators in the ground plane is presented in this paper. The Inverted–U and Iron shaped parasitic resonators are located on the back side of the radiating patch to achieve the band rejection characteristics from 5 to 5.4 GHz for WLAN and 7.8 to 8.4 GHz for ITU band respectively. By cutting a rectangular slot on the ground plane, additional resonance is excited at the higher frequency band, and hence much wider impedance bandwidth can be attained. Applications of the proposed dual band-notched ultra-wideband (UWB) antenna structure with 5.2 GHz and 8.2 GHz center frequencies are demonstrated experimentally. Measured and simulated results of the magnitude of S₁₁, radiation patterns and realized gains show good agreement.     

超宽带信号在室内环境下的性能分析

在对高斯脉冲波形的时域和频域特性进行分析的基础上,采用直接序列扩频方式,进行脉幅调制产生超宽带信号.通过参考IEEE推荐的室内信道模型,重点对室内传播的链路预算进行仿真,对信号的性能进行分析和比较.经过一系列的仿真后,得出高斯四阶导数脉冲波形在实际系统中更具有实用价值的结论.     

Design and Analysis of Antipodal Vivaldi Antennas for Breast CancerDetection

This paper presents the design and analysis of antipodal Vivaldi antennas (AVAs) for breast cancer detection. In order to enhance the antenna gain, different techniques such as using the uniform and non-uniform corrugation, expanding the dielectric substrate and adding the parasitic patch are applied to original AVA. The design procedure of two developed AVA structures i.e., AVA with non-uniform corrugation and AVA with parasitic patch are presented. The proposed AVAs are designed on inexpensive FR4 substrate. The AVA with non-uniform corrugation has compact dimension of mm² or , where is wavelength of the lowest operating frequency. The antenna can operate within the frequency range from 1.63 GHz to over 8 GHz. For the AVA with parasitic patch and uniform corrugation, the overall size of antenna is mm² or It can operate within the frequency range from 1.4 GHz to over 8 GHz. The maximum gain for AVA with non-uniform corrugation and AVA with parasitic patch and uniform corrugation are 9.03 and 11.31 dBi, respectively. The corrugation profile and parasitic patch of the proposed antenna are optimized to achieve the desired properties for breast cancer detection. In addition, the proposed AVAs are measured with breast phantom to detect cancerous cell inside the breast and the performance in detecting cancerous cell are discussed. The measured result can confirm that the proposed AVAs can detect unwanted cell inside the breast while maintaining the compact size, simple structure and low complexity in design.     

一种新型的双陷波特性超宽带天线的设计

提出了一种新型的具有双陷波特性的超宽带天线。该天线在2.8～12 GHz 的宽频带范围内电压驻波比(VSWR)小于2,通过在馈线上引出两个枝节获得了3.3～3.9 GHz 和5～6 GHz 的双陷波特性。通过调节枝节的长度和宽度可以很容易的调节阻带的位置和宽度。仿真和测试结果表明这种新型的天线具有良好的阻抗特性和辐射特性。该天线结构简单,易于加工,便于集成。文中给出了天线的设计以及不同参数对天线性能的影响     

一种微带馈电的双阻带超宽带天线设计

设计了一种具有双阻带的超宽带天线。该天线由一个梯形的辐射单元和一个开有矩形槽的地板构成。并且通过在地板上开L 型和U 型缝隙,实现双阻带特性。该结果表明,天线工作带宽（VSWR<2）为8.6 GHz（2.9～11.5 GHz）,覆盖了UWB 频率范围,在3.2～3.9 GHz 和5～5.9 GHz 处形成了两个阻带,同时,这种天线在整个工作频率范围内有 良好的辐射方向特性。     

A SiGe LC-ladder low noise amplifier with base resistance match,gain and noise flatness for UWB applications

This study presents a 3.1–10.6 GHz ultra-wideband low noise amplifier (UWB LNA) in 0.18 µm SiGe HBT technology. To achieve a good input match, parasitic base resistance in a bipolar transistor and an LC-ladder filter are included into calculations with the common-emitter topology using shunt–shunt capacitive feedback. Both high and flat power gain (S₂₁) and low and flat noise figure (NF) are achieved by adjusting the pole and zero in amplifying stage and quality factors of the fourth-order input network. Design equations for performances such as gain, noise figure and linearity IIP3 are derived especially on gain flatness and noise flatness. LNA dissipates 33 mW power and achieves S₂₁ of 20.65+0.7 dB, NF of 2.79+0.2 dB over the band of 3.1–10.6 GHz. The simulated input third-order intermodulation point (IIP3) is −17 dBm at 10 GHz.