抑制共模噪声的SIW 平衡馈电差分缝隙天线阵*

提出一种利用差分天线在共模激励和差模激励下方向图不同来抑制共模噪声的方法,并基于该理论 设计了6×6 平衡馈电差分SIW 缝隙天线阵进行验证。该天线由6个宽边纵向SIW 缝隙天线子阵列组成。辐射缝隙 被设计为只在差模激励下辐射,达到抑制共模信号的目的。每个天线子阵采用平衡差分馈电方式,使用两个1分6 梳状功分器将6个子阵同时激励。整个天线使用标准PCB 工艺加工,为了测试共模和差模激励,分别设计了带有 180°相移的功分器和T型功分器用来生成差模和共模信号。在差模激励下,天线的最大增益为20.2dBi,S11幅值小 于-10dB 带宽为7.2%(39.6 ~43.8GHz),在共模激励下天线的最大增益为10.1dBi,在整个工作频段内S11幅值大于 -7dB。仿真和实验结果验证了该结构的SIW 缝隙天线对差模信号能够有效地辐射而对共模信号进行抑制。     

低信噪比激光引信回波幅值提取技术

在对激光引信回波进行信噪比分析的基础上,针对低信噪比时峰值检测法在回波幅值提取中相对误差较大的问题,提出了一种采用小波阈值去噪提高幅值提取精度的方法。基于Mallat算法对回波信号进行快速分解与重构,并实际计算了峰值检测法在低信噪比回波幅值提取中的相对误差。研究结果表明,小波阈值去噪能较好地分离回波信号中的高频噪声,减小低信噪比回波幅值提取的相对误差,从而提高了回波幅值提取的精度。     

天线相位中心位置的计算方法

本文提出了一种天线相位中心位置的计算方法,该方法基于天线远场幅度与相位方向图,能够快速计算出天线相位中心位置。首先建立天线相位中心位置与远场相位方向图之间的模型,然后求远场相位SSD对位置偏移的偏导,得到相位SSD的最小值以及此时的位置偏移。在计算相位中心的过程中可以根据要求选取不同的幅度加权方法,在计算结束后,通过补偿后的相位方向图来比较几种加权方法的计算效果。     

Capacity of SSTS for downlink‐distributed antenna systems in multicell environment

We put forward a novel single selection transmission scheme based on maximum desired signal criterion and investigate the capacity of distributed antenna systems in multicell environment. However, for most of the recent literatures, the interference plus noise is treated as Gaussian random variable with fixed variance by the central limit theorem, which ignores the effect of the short‐term fading on interference. To avoid it, non‐central limit theorem is adopted in which the variance of interference plus noise is considered as a random variable with changeable variance influenced by the short‐term fading. Moreover, channels are assumed to suffer from independent identical Rayleigh fading together with propagation path loss, and the closed‐form expression of capacity for distributed antenna systems is derived. Finally, extensive simulations are carried out to validate the theoretical analysis. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of Single‐RF MIMO Receiver with Beam‐Switching Antenna

This paper proposes a single‐RF MIMO receiver that adopts a beam‐switching antenna (BSA) instead of a conventional array antenna. The beauty of the proposed single‐RF MIMO receiver with BSA is that it can be deployed in a very small physical space while achieving a full spatial multiplexing gain. Our analysis has revealed that the use of a BSA inevitably results in the spectrum spreading effect at the RF output, which in turn causes an SNR decrease and adjacent channel interference (ACI). Two novel receiver techniques are proposed to mitigate the issues of redundant sub‐band suppression and ACI avoidance. Numerical analysis results verify the performance improvement from the proposed receiver techniques.     

Modeling and Simulation of New Encoding Schemes for High‐Speed UHF RFID Communication

In this paper, we present novel high‐speed transmission schemes for high‐speed ultra‐high frequency (UHF) radio‐frequency identification communication. For high‐speed communication, tags communicate with a reader using a high‐speed Miller (HS‐Miller) encoding and multiple antennas, and a reader communicates with tags using extended pulse‐interval encoding (E‐PIE). E‐PIE can provide up to a two‐fold faster data rate than conventional pulse‐interval encoding. Using HS‐Miller encoding and orthogonal multiplexing techniques, tags can achieve a two‐ to three‐fold faster data rate than Miller encoding without degrading the demodulation performance at a reader. To verify the proposed transmission scheme, the MATLAB/Simulink model for high‐speed backscatter based on an HS‐Miller modulated subcarrier has been designed and simulated. The simulation results show that the proposed transmission scheme can achieve more than a 3 dB higher BER performance in comparison to a Miller modulated subcarrier.     

一种环形电磁辐射器辐射场的建模与仿真

针对一种环形结构的鱼雷电磁引信辐射器辐射场的计算问题,将该环形辐射器等效成正交磁偶极子,给 出磁矩分量的表达式,通过对各磁矩分量产生的辐射场进行分解与叠加,推导出环形辐射器辐射场的数学模型。仿 真结果表明：该结构的环形辐射器辐射场具有较好的对称性与均匀性,可满足反舰和反潜电磁引信对鱼雷过靶通过 特性的检测需求。     

深水炸弹引信传爆序列设计研究

为了提高深水炸弹引信传爆序列的可靠性,设计了两种方案的传爆序列结构,其中方案Ⅰ是典型的垂直式传爆序列结构,方案Ⅱ为改进型搭接式传爆序列结构。应用非线性有限元软件AUTODYN对两种方案的传爆序列的可靠性进行了数值模拟分析,结果表明:方案Ⅱ提高了传爆的可靠性,缩短了爆轰波稳定转向的时间,对装药间隙值的控制要求相对较低。通过高温、低温和常温环境试验对比分析了两种传爆序列结构的传爆可靠性,结果表明:方案Ⅰ的传爆率为87%,而方案Ⅱ传爆率为100%,方案Ⅱ相比方案Ⅰ传爆率提高了13%。     

防破片飞散抗爆增强型引信焚毁炉的设计

针对开放式炸毁法销毁废旧引信殉爆不彻底,存在危险品飞散、现有引信焚毁炉抗爆能力不足等实际问题,设计了新结构防破片飞散的抗爆增强型引信焚毁炉。该焚毁炉炉体一次铸造成型,能满足较大药量的引信销毁;焚毁炉的喷火管口与炉体内圆切线及水平线均向下形成一定角度,防止了爆炸破片对喷火管的损害,提高了销毁炉的实用效率和使用寿命;底板翻转式排渣,提高了销毁炉的可操作性和工作效率;自动控温自动点火的设计,提高了销毁炉的自动化水平,减少了人工操作的强度和误操作的机率。经销毁试验验证,这种焚毁炉能安全、可靠地将200 g TNT当量以下的废引信产品完全烧毁,满足废旧引信、火工品的销毁要求。     

一种雷达天线翻转机构的设计

为了满足天线自动展开与快速撤收的要求,设计了一种天线翻转机构。重点阐述了该机构的工作原理、结构设计、力学分析及其相应的校核计算。结果表明,该机构性能稳定,天线重复精度高,达到了技术指标要求。