EAST 6MW/4.6GHz低杂波系统天线温度测量设计

为了实现对低杂波系统天线的保护需要测量天线温度,根据天线的特征,选择了K型热电偶作为测量工具,使用快速温度巡检仪采集8路热电偶信号,温度数据由软件远程读取显示;为了克服托卡马克带来的电磁干扰,测量回路使用了光纤通信的方法。结果表明,这种方式能够准确实时地反映出天线温度变化,为日后开展天线热保护工作奠定了基础。     

火焰特征辐射谱线测温方法实验研究

本文利用CCD光纤光谱仪,对不同燃烧状态下的煤粉火焰辐射光谱进行测量.发现通过辐射光谱法测量的火焰温度和使用热电偶测量的火焰温度存在一定的偏差.光谱法的温度较热电偶的温度高约60～160℃,沿火焰行程,热电偶和光谱法测量的火焰温度存在较大的特性差异,光谱法测得的火焰温度沿火焰行程基本不变.同时,光谱法火焰温度的高低受到煤质特性,空气湿度,燃烧过程中的散热条件等因素的影响.     

应用热成象技术测量高温气流温度场

１前言高温风洞的温度高达１７００℃,流速达０．９马赫数。为了测量风洞中气流温度分布的均匀性,通常采用铂铑３０－铂铑１０热电偶温度传感器,但是它只能采用逐点移测法,因此它不可能在同一时刻将一条检测线上气流温度测量出来。同时在高温气流测量时,热电偶接点由...     

航天器热电偶检测系统的设计与实现

热电偶测温广泛应用于航天器真空热试验的温度测量中,目前对于航天器总装阶段的热电偶实施没有一种快速有效的方法进行正确性验证。传统依靠人手触摸测点观察热电偶阻值变化方法的存在一定的局限性,为了提高热电偶检测的准确性和有效性,设计了一种便携式的热电偶检测系统,实现了对热电偶短路、开路和粘贴位置正确性的检测。基于MAX31855的温度采集模块可以快速采集和显示热电偶温度,加热模块的出风口温度控制和加热温度限制能够保证检测过程中航天器的安全性。实际测试表明,该系统具备在现场灵活对航天器表面热电偶进行检测的能力,测试效率高,具有很高的实用性。     

燃烧状态及煤粉粒径对火焰光谱的影响

本文利用CCD光纤光谱仪,对不同燃烧状态下的煤粉火焰光谱进行测量。发现通过光谱法测得的火焰温度和使用热电偶测得的火焰温度存在一定的偏差。光谱法的温度较热电偶的温度高100-700℃,燃烧条件变差时热电偶的温度下降,光谱法的温度升高,两者偏差增大,光谱法温度的波动范围增加。随着一次风煤粉浓度下降, K的发射谱线强度下降。相同燃烧条件下,煤粉细度提高使得光谱法测得的温度下降,温度波动加剧。     

物理实验中测温热电偶冷端补偿方法的改进

本文介绍了两种热电偶冷端温度补偿电路在物理实验测量中的应用及校准方法,对热电偶的工作原理、冷端温度补偿必要性作了说明,并详细介绍了冷端温度补偿过程．     

热电偶冷端补偿电路在物理实验中的应用

本文对热电偶的工作原理、冷端温度补偿必要性作了说明,详细讨论了冷端温度补偿过程.分别介绍了两种热电偶冷端温度补偿电路在物理实验测量中的应用及校准方法.     

热电偶冷端补偿电路的应用

对热电偶的工作原理、冷端温度补偿必要性作了说明，详细讨论了冷端温度补偿过程介绍了两种热电偶冷端温度补偿电路在物理实验测量中的应用及校准方法．     

总温热电偶的最佳设计

随着喷气技术及火箭技术的发展,气流温度测量愈来愈显得重要.采用能以所需准确度直接给出总温的总温热电偶是测量气流温度的有效途径.凭借经验设计的总温热电偶往往难以保证所需的准确度.Haig提出的方法虽然有可能获得所需的准确度,但在分配热电偶误差时仍需凭借经验,很难保证热电偶处于最佳状态.本文介绍的一种按最佳     

应用红外辐射吸收法测量火焰温度

1.引言 使用碳氢燃料的各类发动机和其他高温气体都提出了火焰或高温气体的温度测量问题.传统的一些方法,如热电偶直接测量法,使用时受到某些条件的限制,并干扰原来的物理场分布,给出的温度也不是瞬时值等,而光学测量方法则没有这些缺点.应用红外辐射光谱测量各种物态的温度,具有测量动态范围大,灵敏度高等主要优点,特别适合于测     

Method for eliminating the influence of the antenna — studied medium interface on accuracy in contact radiometric measurements of the medium temperature

We present the results of development of a method for eliminating the influence of an a priori unknown coefficient of reflection from the antenna — studied medium interface on accuracy of radiometric measurements of the medium temperature with the antenna contacting the medium. The method is based on modulation of receiver input noise and permits continuous automatic measurement of the reflection coefficient using the designed circuitry and algorithms for operating the radiometer and processing its output signal. Equations proving the efficiency of this method are obtained. The radiometer block diagram that realizes the proposed method is developed and a device for medical use is manufactured on its basis. Technical performance of the radiometer is given and test results of its measurement accuracy are presented.     

开口波导有效接收面积的测量

 讨论了用开口波导N5作为接收天线的有效面积的测量，给出了测试的原理和方法，并给出了该开口波导的有效接收面积与频率的关系的测试结果。将测试结果与俄国人标定的结果进行了比较。结果表明测试结果是可信的，为准确测试高功率微波源的输出辐射场功率提供了必要条件。该测试方法也适用于其他天线的增益和有效面积的测量。     

Research on Antenna Temperature Contrast of Metal Solid Objects

It is necessary to study the radiation characteristic of metal solid objects for millimeter wave passive guidance. On basis of discussing the grounded theory, the antenna temperature contrast formula of metal solid objects is presented. Furthermore equivalent radiometric section coefficient based on scale-shrinking measuring theory is proposed in favor of engineering applications. The data error between 8mm theoretical calculation and actual measurement are mostly below 1K. So equivalent radiometric section coefficient gives a virtual way for engineering calculation and measurement of metal solid objects.     

Antenna phase pattern measurements at millimeter wave frequencies using the differential phase method with only one power meter

The differential phase measurement method has been improved to need the use of only one power meter instead of three power meters. This enables accurate antenna phase pattern measurements with a simplified set-up, accompanied by the reduction in cost. All advantages of the differential phase measurement method are still also available, e.g. there is no need to phase lock oscillators or to use rotary joints. The measurement results for an antenna at 110 GHz are presented. A good agreement with earlier data was obtained.     

Design of a low-frequency miniaturized piezoelectric antenna based on acoustically actuated principle

An acoustically actuated piezoelectric antenna is proposed for low frequency (LF) band in this paper. The proposed antenna is theoretically calculated, numerically optimized by the finite element method (FEM), and experimentally analyzed. The measurement results show that the near-field radiation pattern of the piezoelectric antenna is similar to that of the electric dipole antenna. The radiation efficiency of the piezoelectric antenna is 3－4 orders of magnitude higher than that of electrically small antenna (ESA), with their sizes being the same size, and the maximum transmission distance obtained experimentally is 100 cm, which can be improved by increasing the input power. In addition, the gain, directivity, and quality factor of piezoelectric antenna are also analyzed. In this paper, traditional antenna parameters are creatively used to analyze the performance of piezoelectric antenna. The research conclusions can provide reliable theoretical basis for realizing LF antenna miniaturization.     

高功率微波天线增益测试方法研究

介绍了几种天线增益的测试方法,并根据高功率微波(HPM)天线的特殊性,提出了一种窄脉冲激励下HPM天线增益测试方法。利用直接功率测量方法,将窄脉冲信号源作为发射信号源,通过标定不同脉冲宽度下接收天线的最大接收功率,开展实验研究,测得窄脉冲条件下天线的增益值。测试结果表明:在脉冲宽度大于25 ns的微波脉冲激励HPM天线时,天线增益测试结果与连续波条件下天线增益测试结果相同。     

一种自放电双锥天线激励电压的测量方法

采用一种通过测量脉冲源对天线的充电电流,来间接测量天线放电激励电压的方法。首先建立了实际电路的理论仿真模型,通过理论仿真证明了该方法的可行性。然后在双锥天线的不同绝缘工作气压下,对其充电电流进行了测量。由天线的充电电流推导出了在不同工作气压下天线的电压波形和放电激励电压。该种方法无需对天线进行改造,不会引进寄生参数,不会影响被试对象的工作状态,且在工程上易于实现。     

星载极化相关型全极化微波辐射计天线交叉极化校正技术 (II) : 校正试验

创建了地球场景数据集, 结合全极化微波辐射传输模型, 仿真了地球场景亮温. 基于自主推导的全极化天线温度方程, 通过GRASP9软件生成天线方向图, 模拟了辐射计的天线温度. 进而利用多元线性回归方法, 求取了天线交叉极化校正M矩阵, 实现了对星载极化相关型全极化微波辐射计天线交叉极化的校正. 试验结果表明: 天线温度与地球场景亮温之间具有良好的线性关系; 天线交叉极化对全极化微波辐射计正交通道亮温影响明显, 尤其以对垂直极化亮温误差的影响最为显著; 校正后各通道的天线交叉极化得到了有效的减小, 交叉极化优于-23 dB, 极化纯度大于99.5%, 采用M矩阵校正及消除天线温度中交叉极化亮温影响的方案是切实可行的. 该校正技术可以实现星载极化相关型全极化微波辐射计在轨运行后对于天线交叉极化的最终校正. 关键词： 全极化微波辐射计 天线交叉极化 天线温度方程 M矩阵')" href="#">M矩阵     

Complementary electric-LC resonator antenna for WLAN applications

In this paper, a metamaterial antenna based on complementary electric-LC (CELC) resonator is proposed. The antenna consists of slot-loaded ELC on the ground plane as the main antennas radiating element and excited by a microstrip line. The CELC resonator is characterized by single-negative magnetic moment excited by coupling between the microstrip transmission line and slot-loaded CELC. The peak realized gain and efficiency of 2.63 dB and 86 % are obtained, respectively, at resonance frequency. Simulation and measurement results are presented to validate the design. The antenna is suitable for WLAN applications (2.39–2.48 GHz).     

基于左手材料的高增益双频带微带天线

左手材料具有平板透镜聚焦效应,突破电磁波的衍射极限实现倏逝波的放大,其覆盖于微带天线上方,可以提高天线增益。设计了一种应用于UHF和WLAN的双频微带天线,通过在接地板上刻蚀"己"字形弯折缝隙的方法实现双频谐振。为了改善微带天线低频段的增益,设计了一种新型的哑铃型结构双频段左手材料,将其作为微带天线的覆层。测试结果表明,覆层左手材料微带天线的低频段和高频段的峰值增益分别为2.1dBi和7.4dBi。