微扰和标定技术测量薄膜微波介电常数

提出了一种测量介质薄膜微波段介电常数的方法.该方法基于金属空腔谐振器微扰理论,用已知介电常数的基片作为标样,标定测量系统的有关参数,然后分别测量空腔、基片插入空腔、镀有介质薄膜的基片插入空腔三种情况下的谐振腔谐振频率,计算出镀覆于基片上介质薄膜的微波复介电常数.本文SiO2和MgTiO3-CaTiO3(MCT)介质陶瓷薄膜作了实验测量验证,结果表明该方法具有良好的测量精度(小于6%).     

生物介质复介电常数的微扰法测量

由谐振腔微扰理论出发，得到复介电常数计算式，测量了不同浓度的NaCl溶液及小鼠血液、肿瘤细胞悬液等样品的复介电常数；所得结果较为精确，证明了本测量系统的可靠性；对测量的系统、方法、仪器所引入的误差做了一定分析。     

同轴传输反射法测量高损耗材料微波介电常数

同轴传输反射方法可以用来测量高损耗材料的微波介电常数。该方法将环形样品嵌入同轴线内,通过测量样品两端的散射系数来确定材料的微波介电常数。文中介绍了测量原理及测量系统,测量了一种石蜡基混合样品的微波介电常数,并通过改进的Bruggeman数学模型,推算出其中陶瓷材料的介电常数。     

六端口反射计测量复介电常数的改进方法

提出了六端口反射计测量介质材料复介电常数的一种改进方法,新的算法使测量面与参考面分离,消除了传统测量方法中测量面与参考面无法完全重合引入的误差.给出超越方程的简单准确的数值解法,得到了相对介电常数多值间隔与测量频率和样品长度的关系.实际测量结果表明本文方法的有效性和实用性.     

微波铁氧体吸收剂复介电常数的研究

对W型六角晶系铁氧体吸收剂复介电常数进行了研究，通过实验着重研究配方中Fe2O3的掺入量对介电常数的影响，研究发现，在分子式正分配方附近复介电常数ε的实部值ε′与虚部ε″值随Fe2O3的掺入量增加而升高，对材料中出现二价铁离子Fe^ 对介电常数的影响以及介电常数随频率的变化进行了分析。     

基于VC++的介质复介电常数带状线法自动测试系统的研究

随着微波技术的迅猛发展,对微波介质材料提出了新的要求,对介质材料的各种性能的测量有了更多的需求,复介电常数是介质的一个主要参数,本文就微波介质复介电常数测量的带状线法进行了一个简单的介绍,并重点就基于VC++所编制的自动测量程序做了相关的论述。自动化测量可以大大提高我们的工作效率。     

传输/反射法测量固体复介质材料介电常数

介绍/传输反射法测量固体介质材料复介电常数等关键技术难点,通过建立固体介质材料的介电谱和磁谱测量装置,开展复介电常数、复磁导率、复损耗角正切测量技术研究,在30 MHz～18 GHz采用空气线同轴传输的方法、在18～50 GHz采用三段波导传输的方法,实现了30 MHz～50 GHz全频段固体介质材料电磁参数的测试能力,提出了复介电常数、复磁导率、复损耗角正切测量的数学模型,编制了材料测试软件,实现了同轴和波导的全频段测量。     

测量介质材料复介电常数的准光腔法

针对介质材料,介绍了在毫米波段和亚毫米波段能够准确测量其复介电常数的准光学谐振腔法。准光学谐振腔具有高Q值、使用简便、样品放置容易等许多优点,能够有效地完成介质材料电介质参数精密测量的任务。这种谐振腔为半球型并由一个平面镜和一个凹面铜镜组成,采用固定腔长法或固定频率法进行测量。另外,还介绍了准光学谐振腔的测试系统和最新的研究成果及改进方法,例如测量多层薄膜及在更高频段的测量方法。     

介质材料复介电常数测试的同轴线谐振腔法研究

利用同轴线谐振腔对介质材料复介电常数进行测试得到其谐振频率f0,品质因数Q0通过联立两个独立方程,求解出tanδ(即ε’’/ε’),同轴线谐振腔传输的为TEM波,由谐振频率f0根据相关公式求解出ε’,从而掌握该材料的特性参数。     

一种新的复介电常数自由空间测量技术研究

提出了一种新的复介电常数的自由空间测量方法,该方法将介质周期结构引入到复介电常数的测量中。运用多模网络理论与严格的模匹配技术,系统分析了加损耗样品层的介质周期结构的散射特性,详细研究了样品复介电常数对反射峰幅度和中心频率的影响。该测量方法不仅克服了传统自由空间法的不稳定性和相位模糊性问题,而且具有谐振法可以对低损耗介质精确测量且测量过程简单的优点,为复介电常数的精确测量提供了一种新的测量方法和重要的理论指导。     

A Two Coupler Method for Measurement of Complex Permittivity of Dielectric Materials at Microwave Frequencies

This paper describes two coupler method for measurement of dielectric properties of materials, at microwave frequencies. Two waveguide sections, fed from a common source, are coupling power into a waveguide filled with dielectric. The phase and attenuation constants are computed from the values of phase and attenuation adjustment required for cancellation of the signal in the dielectric filled waveguide. The two coupler method is particularly applicable for measurements of dielectric properties of aerosols and gases.     

Complex Permittivity of Planar Building Materials Measured With an Ultra-Wideband Free-Field Antenna Measurement System

Building materials are often incorporated into complex, multilayer macrostructures that are simply not amenable to measurements using coax or waveguide sample holders. In response to this, we developed an ultra-wideband (UWB) free-field measurement system. This measurement system uses a ground-plane-based system and two TEM half-horn antennas to transmit and receive the RF signal. The material samples are placed between the antennas, and reflection and transmission measurements made. Digital signal processing techniques are then applied to minimize environmental and systematic effects. The processed data are compared to a plane-wave model to extract the material properties with optimization software based on genetic algorithms.     

粘弹材料复弹性模量的全频段表征与测量

1引言 声学上常用的吸声材料多为高阻尼的有机材料,这类材料在力学性能上表现为恒应力加载下的蠕变行为和恒应变加载下的应力松弛行为,在声学性能上表现为材料响应比激励明显滞后,即损耗角较大,并且材料的性质强烈依赖于激励频率.     

Thin Film Tl-Based HTS Microwave Devices

Linear microstrip resonators suffer from high peak current density inside the resonators which limit the power handling characteristics. To realise higher power filters for cellular applications it is possible to use two dimensional microstrip resonators (such as disks) to equalise the internal current distribution. We have designed and tested such microstrip resonators, fabricated from TBCCO 2212 thin films deposited by RF sputtering onto 10×10mm and 20×20mm LaAlO₃, substrates. The R_s of such films has been measured at 24 GHz using a sapphire dielectric resonator and shown to be less than 500 scaled to 10 GHz and at 80K. Q values of 3-12 GHz disk resonators have demonstrated considerable improvements when compared to both linear HTS microstrip resonators and comparable copper disk resonators. Additionally, the power handling of such resonators has been shown to be superior to that of conventional linear resonators fabricated from similar material.     

微波铁氧体吸收剂复磁导率和复介电常数的温度特性研究

本文对（Ｚｎ＿（１－ｘ）Ｃｏ＿ｘ）＿２－ｗ型六角晶系铁氧体吸波材料的复磁导率μ＿ｒ和复介电常数ε＿ｒ的温度特性进行了研究。实验发现当温度从－２５℃升至１００℃时，复磁导率的实部μ＇＿ｒ值从１．５１降至１．３０，虚部μ″＿ｒ值从０．１９降至０．１４，复介电常数的实部ε′＿ｒ值从６．５０升至７．１０，虚部ε″＿ｒ值从１．７０升至１．８０，理论上对电磁参数随温度变化特性进行了分析讨论。     

International Comparison of Complex Permittivity Measurement at 9 GHz

Dielectric constant and loss measurements made by three government laboratories (of the USSR, Canada, and the U. S. A.) are compared. The two materials measured were glasses. The measurements utilized cavity resonators in the H01n mode. The errors in dielectric constant reported by the laboratories were usually ± 0.3 percent; actual differences between laboratories of the average corrected results were only ± 0.05 percent. The loss tangent results disagreed when multimoding occurred; however, the errors may be as low as ± 0.00002 or ± 3 percent, whichever is the larger, if multimoding is avoided.     

多晶铁纤维吸收剂微波复磁导率和复介电常数的理论计算

由麦克斯韦方程出发,导出了多晶铁纤维吸收剂微波复磁导率和复介电常数的理论计算公式;通过对５ＧＨｚ频率点多晶铁纤维吸收剂的数值计算,分析了多晶铁纤维的直径、长径比及电导率等对其电磁参数的影响。