A Novel Unit Cell for Active Switches in the Millimeter-Wave Frequency Range

This paper presents a novel transistor unit cell which is intended to realize compact active switches in the high millimeter-wave frequency range. The unit cell consists of the combination of shunt and common gate transistor within a four-finger transistor cell, achieving gain in the amplifying state as well as good isolation in the isolating state. Gate width-dependent characteristics of the unit cell as well as the design of actual switch implementations are discussed in detail. To verify the concept, two switches, a single pole double throw (SPDT) switch and single pole quadruple throw (SP4T) switch, intended for the WR3 frequency range (220–325 GHz) were manufactured and characterized. The measured gain at 250 GHz is 4.6 and 2.2 dB for the SPDT and SP4T switch, respectively. An isolation of more than 24 dB for the SPDT switch and 12.8 dB for the SP4T switch was achieved.     

长球的双基地雷达截面积计算分析

雷达截面积（RCS）是目标的一个重要特性参数，在理论上分析计算目标的雷达截面积有着重要的实际意义。基于几何光学能量传播的思想，首先推导了一种长球双基地雷达截面积的计算方法，并以此分析了长球的双基地雷达散射截面积，最后对算法进行了仿真计算，仿真结果表明长球的RCS呈现极强的方向性。     

用空间传播和RCS模型研究RFID装置最大识别距离

通过自由空间传播模型和雷达散射横截面（RCS）模型,研究了反向散射射频识别（RFID）装置的最大识别距离。用高频电磁场仿真软件FEKO对折叠偶极子标签天线进行了建模仿真,得到天线的远场辐射方向图、输入阻抗以及在不同负载情况下天线的单站RCS值。经过理论分析和仿真计算,由两个电波传播模型分别得出RFID装置可能的最大识别距离。最后比较了两种模型的计算结果,较小的距离即为该反向散射RFID装置的最大识别距离。     

超电大复杂目标RCS缩比模型预估方法

本文提出用缩比模型计算电大目标雷达散射截面（RCS）的理论。通过复杂目标近远场电磁散射理论模型的分析得到，目标的雷达截面和目标的几何尺寸及工作波长有关系。当电尺寸相同时，目标雷达散射截面和其几何尺寸的平方成正比，缩比模型计算既适用于近场，也适用于远场。     

A New Codebook Design Scheme for Fast Beam Searching in Millimeter-Wave Communications

To overcome imperfection of exhaustive based beam searching scheme in IEEE 802.15.3c and IEEE 802.11ad and accelerate the beam training process, combined with the fast beam searching algorithm previously proposed, this paper proposed a beam codebook design scheme for phased array to not only satisfy the fast beam searching algorithm＇s demand, but also make good use of the advantage of the searching algorithm. The simulation results prove that the proposed scheme not only performs well on flexibility and searching time complexity, but also has high success ratio     

Reflectance Measurement of Lossy Metal Meshes in the Millimeter-Wave Range

The method of power reflectance measurement of small lossy metal meshes is suggested by evaluating the measured reflection coefficient in the vicinity of a resonance mode of quasi-optical resonator. The resonator is described by the equivalent circuit that includes coupling ohmic losses of the mesh. The multi-points reconstructing algorithm is suggested to restore power reflectance. This particular technique is suitable for reflectance measurements of lossy metal meshes and wire grids having overall small dimensions which are not relevant when employing standard free space techniques. Its validity is illustrated by reflectance measurements in W-band.     

一种新型的单边带调制技术

从理论和实验两方面研究了一种新型单边带调制(SSB)技术,通过在中心站合适设置单臂强度调制器的偏置电压,使调制器产生的奇数边带被抑制,采用滤波器滤除其中的一个二阶边带,即可产生单边带信号.用该新型的单边带调制技术产生的光毫米波理论上可以传输148 km.同时搭建了实验系统,采用10 GHz的本振信号源与2.5 Gbit/s的数字信号混频后驱动单臂强度调制器产生抑制奇数边带的调制信号,再通过一个滤波器得到20 GHz的单边带毫米波,还得到了不同载波边带比(CSR)情况下的毫米波眼图.通过实验分析不同载波边带比对传输性能的影响,发现载波边带比为0 dB时,传输性能最佳.     

一种变周期区间内随机信号的监控方案

利用Cyclone III系列FPGA实现了对变周期区间内随机信号的监控,并提供一种随机反馈信号的监控算法。     

一种改进的光载波抑制产生光毫米波的方法

为了延长光毫米波的传输距离,提出了一种改进的光载波抑制产生光毫米波的方法。在中心站采用马赫-曾德尔调制器将射频信号调制到光载波上产生光载波抑制调制光信号,再将产生光信号的2个边带分离,将2.5Gbit/s数据信号调制到其中1个边带上,再与未调信号耦合后产生光毫米波并通过光纤传送至基站。在基站中通过光电转换器产生电毫米波。从理论上分析了这种光毫米波的传输特性并通过实验验证了光毫米波在光纤中可以传输40km。仿真和实验结果表明,这种方式产生的光毫米波具有很好的抗色散能力,延长了传输距离。     

一种基于DPMZM的16倍频光生毫米波方案

为提高光载无线(RoF)中光生毫米波的倍频系数及降低系统的复杂度,提出了一种基于双平行马赫曾德尔调制器(Dual-Parallel Mach-Zehnder Modulator, DPMZM)和偏振复用技术的抑制载波的16倍频毫米波信号产生方案。推导了理想情况下倍频方案的产生机理。在仿真实验中,分别分析了调制器调制指数、消光比、电移相器相移、偏振器件角度漂移等非理想因素对系统光边带抑制比(OSSR)和射频杂散抑制比(RFSSR)的影响。结果显示,当合理设置各参数的取值范围,其对应的OSSR和RFSSR的饱和值高达29.88 dB和23.9 dB。该方案在一定程度上简化了16倍频的系统模型且生成的毫米波信号性能较为高效、频谱纯度较好,对实际系统设计具有一定的参考价值,为微波光子学的发展提供了新途径。     

Excess Propagation Loss of Semi-Closed Obstacles for Inter/Intra-Device Communications in the Millimeter-Wave Range

The ever decreasing geometrical dimensions of electronic devices makes miscellaneous cables or connectors of relatively large dimensions unwanted. Thus, wireless inter/intra-device communications in the millimeter-wave range become a topic of recent interest. In this paper, the excess losses of three groups of typical semi-closed obstacles (connectors, heatsinks, and printed circuit boards) in inter/intra-device communications are measured and empirically modeled. Specific coefficients for each of the obstacles are estimated to describe the excess loss in the millimeter-wave band. Validation shows that the empirical model structure combined with the specific coefficients can provide an effective and simple way to include various semi-closed obstacles in the network planning, simulation, and design of inter/intra-device communications.     

Millimeter-Wave Silicon IMPATT Sources and Combiners for the 110-260-GHz Range

This paper reports recent progress in CVV and pulsed silicon IMPATT sources in the 110-260-GHz frequency range. Pulsed output power levels of 3, 1.3, and 0.7 W, and CW output power levels of 110, 60, and 25 mW have been consistently achieved from single-drift IMPATT diodes at 140, 170, and 217 GHz, respectively. A Read-type IMPATT diode that generated good output power over a wide frequency range was fabricated. A bridged double-quartz standoff package was developed and successfully used for the entire frequency range. Power combiners at center frequencies of 140 and 217 GHz were developed with peak output power of 9.2 and 1 W, respectively.     

Nonuniform Layer Model of a Millimeter-Wave Phase Shifter

The electromagnetic wave propagation of millimeter waves in dielectric waveguides with thin surface plasma layers is characterized. The phase and attenuation of a 94-GHz wave are computed for various surface plasma layer thicknesses as a function of earner density levels. The electron/hole pairs generated in the vicinity of the dielectric waveguide surface by photo excitation are assumed to have an exponential profile due to either carrier diffusion or the exponential absorption of the optical field. Field computations made for a uniform plasma layer are compared with those of the nonuniform plasma to illustrate the effects of the exponential tails of the carrier profiles on both the phase and attenuation of the millimeter wave. The thin plasma layers slightly affect the field profile of the transverse electric modes (fields polarized parallel to the plasma layer). The transverse magnetic fields are highly distorted at plasma densities greater than 10/sup 16/ cm/sup -3/.     

Flower Constellation of Millimeter-Wave Radiometers for Tropospheric Monitoring at Pseudogeostationary Scale

In this paper, the design of a minisatellite FLOwer constellation (FC), deploying millimeter-wave (MMW) scanning RADiometers, namely, FLORAD, and devoted to tropospheric observations, is analyzed and discussed. The FLORAD mission is aimed at the retrieval of thermal and hydrological properties of the troposphere, specifically temperature profile, water-vapor profile, cloud liquid content, and rainfall and snowfall rate. The goal of frequent revisit time at regional scale, coupled with quasi-global coverage and relatively high spatial resolution, is here called pseudogeostationary scale and implemented through a FC of three minisatellites in elliptical orbits. FCs are built on compatible (resonant) orbits and can offer several degrees of freedom in their design. The payload MMW channels for tropospheric retrieval were selected following the ranking based on a reduced-entropy method between 90 and 230 GHz. Various configurations of the MMW radiometer multiband channels are investigated, pointing out the tradeoff between performances and complexity within the constraint of minisatellite platform. Statistical inversion schemes are employed to quantify the overall accuracy of the selected MMW radiometer configurations.      

A Statistical Radio Range Model for a Robot MANET in a Subterranean Mine

We present a statistical model for the radio range between robots in a Mobile Ad hoc NETwork (MANET) deployed in an underground mine. Such unmanned mobile robotic networks could potentially be used in hazard mitigation and search and rescue in tunnel environments such as mines and subways, as well as in building environments. In addition to fading characteristics, our model is able to represent the variable nature of the propagation path-loss exponent. To support our model, we present path-loss measurements made in a real mine. The usefulness of our model lies in the fact that it represents an overall propagation model for a mine and therefore can be used to calculate the wireless connectivity probability of an arbitrary node in the network without requiring a detailed physical representation of the MANET within the mine.      

基于RCS信息的雷达目标大小分类方法

由于低分辨率雷达信息量有限,不能对目标的属性特征等做出精确的判断分类,只能做到粗略的分类判断.因此,文中给出了一种雷达散射截面(RCS)统计信息的低分辨率雷达对目标大小的分类方法.讨论了一种利用最大最小距离的聚类模式识别算法.并通过对实测数据的处理对算法进行了验证,证实了利用RCS统计特性结合最大最小距离的聚类模式识别算法对目标进行大小分类的可行性.     

地面平面场RCS 测量异地定标误差分析

地面平面场是用于进行全尺寸或缩比目标模型静态散射特性测量的室外场地。该文从地面平面场的特点入手,分析了在进行目标雷达散射截面(RCS)测量时,目标和定标体因受到测量环境影响而产生的定标误差。在简要阐述地面平面场中的异地定标技术的基础上,综合考虑地面反射和天线方向性两方面的因素,研究了定标体回波强度与放置位置的关系,分析了地面平面场与自由空间的定标之间的差异以及由此所带来的测量误差。最后,通过计算机仿真得到了异地定标误差随定标体测量距离、测量频率以及天线波束宽度的变化规律。通常情况下,定标体放置在靠近目标的位置有利于减小异地定标误差。      

用迭代物理光学法分析导弹的耦合散射效应

主要介绍用迭代物理光学法(IPO)计算存在散射耦合的导弹雷达散射截面(RCS)。主要原理是用迭代的方法来求解磁场积分方程(MFIE),以求得存在耦合部件的RCS。研究表明,在IPO的计算过程中不仅需要判断入射波的照射面和阴影面,而且要判断互相耦合的散射体之间的可见性,本文给出解决该问题的相应方法。对遮挡问题判断的准确性直接会影响迭代过程的收敛性,同时影响收敛性的因素还有电磁波相对于散射体的反射次数。最后,通过利用IPO方法与PO方法的计算结果的比较,分析导弹的耦合散射效应。     

Design and Analysis of a Millimeter-Wave Direct Injection-Locked Frequency Divider With Large Frequency Locking Range

In this paper, direct injection-locked frequency dividers (ILFDs), which operate in the millimeter-wave (MMW) band, are analyzed. An analytically equivalent model of the direct ILFDs is developed, and important design guidelines for a large frequency locking range are obtained from it. These guidelines are: 1) maximize the quality factor of the passive load; 2) maintain low output amplitude; and 3) increase the dc overdrive voltage of the input device. A direct ILFD without varactors is designed and fabricated using a 0.13-mum bulk CMOS process to verify the developed model and design guidelines. A pMOS current source is used to restrict the output amplitude and to increase the dc overdrive voltage of the input device to achieve a large frequency locking range. The size of the input device is only 3.6 mum/0.12 mum and the measured frequency locking range is 13.6% at 70 GHz with a power consumption of 4.4 mW from a supply voltage of 1 V. In short, the proposed divider has the potential to be integrated into an MMW phase-locked loop system.     

SITH负阻转折特性的分析模型

提出了一个用于分析ＳＩＴＨ正向阻断态的新模型。这个模型在结构上类似于ＳＣＲ。这样,就可以把ＳＩＴＨ的二维分析简化为ＳＣＲ的一维分析。我们应用了这个模型来分析ＳＩＴＨ的负阻特性并且计算出了阳极正向转折电压,计算结果与实际测量值相符合,从而证明了这个模型的合理性。