Measurement of Low-Loss Dielectric Materials Using Dielectric Rod Resonator

To obtain the complex permittivity of low-loss dielectric materials at 60 GHz, a measurement method is developed. Using a dielectric rod resonator excited by a dielectric waveguide, effective conductivity of conducting plates for short circuiting the resonator is determined. The complex permittivity of the dielectric rod is determined by the resonant frequency and unloaded quality factor of the TE_0m1-mode resonator. Moreover, the complex permittivity of single crystal sapphire, polycrystalline ceramics, and cordierite has been investigated in virtue of numerical simulation. For all the measured specimens in this study, the proposed method is seen to provide much better accuracy for values.     

Measurement of Dielectric Properties for Low-Loss Materials at Millimeter Wavelengths

We describe here a system for accurate measurement of the dielectric properties of very low-loss materials in the 130 to 170 GHz frequency range. This system utilizes an open resonator with a quality factor ∼ 1 × 10⁶. Resonance curves for this resonator are acquired with a commercial spectrum analyzer equipped with an external millimeter-wave harmonic mixer. The excitation source is a backward-wave oscillator locked to the spectrum analyzer local oscillator via a digital phase-locked loop. This system permits rapid and accurate measurement of resonance curve line widths, permitting determination of loss tangents down to the 10^-6 range. Results are reported for silicon carbide (SiC), CVD diamond, sapphire, and quartz.     

平行板谐振法测量微波介质陶瓷介电性能

对平行板谐振法测量微波介质陶瓷的基本原理进行了阐述。介绍了该方法的硬、软件构成及其操作注意事项,并给出了部分测试结果。该方法具有测量简单、快速、准确的优点,但不适用于测量介质损耗较大的微波介质陶瓷。 r的测量误差为0.5%左右,Q值的测量误差为15%以下。     

微带线法测量微波材料的复介电常数

电磁波传输介质的电磁参数的准确测量,对材料的实际应用十分重要。研究微波材料介电常数的微带线测量方法,通过正演和反演过程的求解分析,对不同介电常数的材料进行了实际计算,同时还对测试误差进行了简要分析。结果表明,微带线测试微波材料的复介电常数方法可行,测量过程较为简单,测量结果准确。     

Microwave Dielectric Properties of Plant Materials

Three waveguide transmission systems covering the 1-2, 3.5-6.5, and 7.5-8.5 GHz bands were used to measure the dielectric properties of vegetation material as a function of moisture content and microwave frequency. The materials measured included, primarily, the leaves and stalks of corn and wheat. Dielectric measurements also were made of the liquid included in the vegetation material after it was extracted from the vegetation by mechanical means. The extracted liquids were found to have an equivalent NaCl salinity of about 10 per mil, which can have a significant effect on the dielectric loss at frequencies below 5 GHz. The results of attempts to model the dielectric constant of the vegetation-water mixture in terms of the dielectric constants and volume fractions of its constituent parts (i. e., bulk vegetation, air, bound water, and free water) are discussed. Additionally, measurements of the temporal variations in the total attenuation at 10.2 GHz are presented for a corn canopy and a soybean canopy.     

一种微波介质谐振器复介电常数测试方法

介绍了一种简单的微波介质谐振腔的设计及性能参数的计算方法，给出了相对介电常数ε1、介质损耗tan δ的详细求解方程，为微波介质陶瓷性能参数的测量提供了一种简单而有效的方法。     

A New Microwave Method for Electrical Characterization of Low-Loss Materials

A microwave method is proposed to effectively determine the complex permittivity of low-loss dielectric materials. The method uses raw scattering parameter measurements of an empty cell and a measurement cell (a waveguide or coaxial-line section) with one sample for its two configurations. There are three advantages of the proposed method. First, it does not necessitate any calibration to carry out the microwave measurements. Second, it eliminates the measurement errors arising from sample thickness and inhomogeneity present in the second sample, which is required by other methods. Third, it uses transmission-only scattering parameters of the sample in the theoretical formulations so that it may decrease the measurement errors happening from the phase uncertainty in reflection scattering parameters. The measurement results of two low-loss dielectric materials confirm the accuracy of the proposed method.      

用复合谐振腔法测量介质谐振器材料的介电特性

本文根据Barlow提出的在TE(01n)模谐振腔上耦合一段截止波导构成复合腔的原理，首次在C波段对介质谐振器材料的介电性能进行了测量，并从理论上证明了该方法对相对介电系数有很高的测试灵敏度，本文给出了几种介质谐振器材料的测试结果，最后就样品厚度对测试精度的影响作了分析。     

Millimeter Wave Measurement of the Low-Loss Dielectric in Vacuum Electronic Devices with Reflection-Type Hemispherical Open Resonator

Accurate dielectric properties are of great importance for the design and fabrication of the input and output windows in vacuum electronic devices. A reflection-type hemispherical open resonator (RTHOR) was designed through theoretical analysis and numerical simulation and also was utilized to measure the dielectric properties of the windows material sapphire. Compared with the two ports measurement, a simplified measurement system to obtain the dielectric performance was proposed and the RTHOR with only one coupling aperture was directly connected to a W-band vector network analyzer (VNA). The material properties can be easily calculated through the VNA measured port reflection coefficient (S₁₁) resonant curve. Investigation shows that the permittivity and the loss tangent of the measured sapphire, which is used to construct the input and output window, is respectively about 9.40 and 1.80?×?10^?4 at room temperature in W-band, which agree well with the reported results. Measured results also show that the simplified measurement system can provide a high accuracy for the measurement of low-loss dielectric in a relatively convenient way.     

Application of Inverted Strip Dielectric Waveguides for Measurement of the Dielectric Constant of Low-Loss Materials at Millimeter-Wave Frequencies

An entirely new method for measuring dielectric properties of slab-type materials is developed by using a novel dielectric waveguide structure originally designed for millimeter-wave integrated circuits. The method entails the measurement of the stopband of the grating structure created in the dielectric waveguide. Several examples of measurement results are reported.     

微波介质陶瓷材料介电性能间的制约关系

微波介质陶瓷材料的三个主要参数相对介电常数εr、品质因数Q和谐振频率温度系数之间存在一定的关系。采用一维双原子线性振动模型,分析了微波介质陶瓷材料的εr、Q影响因素和它们之间的相互制约关系;采用Clausius-Mosotti方程,分析了谐振频率温度系数的影响因素以及它和εr之间的相互制约关系。讨论了提高高介微波介质陶瓷材料性能的途径,发现采用同电价质量较轻的离子取代,在基本不影响介电常数的情况下具有提高材料的Q·f值的可能性。     

介质腔稳频FET压控振荡器

本文介绍一种新颖的,用介质腔稳频的压控振荡器,叙述了其电调原理,设计考虑,并给出了实验结果;该振荡器的中心频率f_0=5.415GHz;电调带宽△f≥20MHz(V_0=G～-15v);输出功率p_o≥15mw;频率温度系数T≤3.2ppm/℃;在偏离载频100kHz处的调频相位噪声<-90dBc/Hz,该振荡器性能已满足使用单位的要求。     

微波介质陶瓷介电常数测量的简单方法

应用等效网络法分别测量了空气、聚四氟乙烯及微波介质陶瓷材料片状试样的介电常数。理论分析计算与实验结果表明,该方法在无损测量片状微波介质陶瓷材料试样的介电常数中是可行的,且有模型简单、计算量小、精度较高及操作容易等特点。是一种无损测量片状微波介质陶瓷材料介电常数的简单方法。     

低耗液体材料微波复介电常数的准确测试技术

本文提出了一种低耗液体材料微波复介电常数测试技术，利用一腔多模的ＴＥＯｍｎ高Ｑ圆柱测试腔，可对低耗液体材料的ε′γ和ｔａｎδ进行准确地测量．测试ε′γ的不确定度为±０．５％，ｔａｎδ的不确定度为±５．８％，且在一定频带范围内考察了ε′γ和ｔａｎδ３随频率变化特性。该技术测试简便、迅速、自动化程度高，可适用于多种低耗液体材料的测试。     

微波小型化固态介质谐振器振荡器的发展

介绍了近年来微波小型化固态介质谐振器振荡器（ＤＲＯ）研究方面的新成就。重点介绍了介质材料、ＤＲＯ的频率调谐特性、相位噪声性能的优化、ＤＲＯ的拓展设计以及焊封和可靠性。     

有孔圆柱介质谐振频率的自动测试方法

从求解Maxwell方程本征值出发,采用MATLAB中PDE工具箱,借助可二维作图的开槽圆柱谐振器,计算出有孔圆柱介质谐振器的谐振频率。求解结果与矢量网络分析仪测量结果吻合,误差在千分之四以内。且该有限元法计算软件采用MATLAB编写,可方便地被调用于矢量网络分析仪的VEE测试软件中,较好解决有孔及变形圆柱介质谐振器的设计、测量和微调等问题,特别是矢量网络分析仪的快速自动测量中。     

A Microwave Method for Noniterative Constitutive Parameters Determination of Thin Low-Loss or Lossy Materials

A noniterative transmission-reflection method is proposed for instant measurement of constitutive parameters of thin samples attached to a sample holder. It uses reflection-only measurements for constitutive parameters determination thanks to the asymmetric nature of the structure (holder sample). In addition, the method can also measure the complex permittivity of the sample holder from transmission and reflection measurements. The disadvantage of the method, however, is that it requires different reflection-only measurements, and hence, a suitable selection of holder thickness and permittivity combination. In case similar reflection properties of the structure are measured, the noniteratively measured constitutive parameters by the proposed method can be utilized as an initial guess in a search algorithm, which uses transmission and reflection measurements. In this way, the proposed method provides a suitable initial guess for electrical properties of materials under test with no prior information.      

改进矩形腔微扰法测试微波电介质复介电常数

本文讨论了测试电介质微波复介电常数的矩形腔微扰法。对介质样品加载后的ＴＥ１０ｎ模矩形腔腔内场进行了理论分析。通过对腔内场的数值求解，得出了与微扰公式相似的、已修正的准确计算公式。     

Precise Dielectric Measurements of Low-Loss Materials at Millimeter and Submillimeter Wavelengths

Transmission dispersive Fourier transform, spectrometry (DFTS) has been used for the measurements of both real and imaginary parts of the complex relative permittivity of low-loss materials at millimeter and submillimeter wavelengths. The materials investigated include cis and trans decalin and polypropylene.     

Dielectric Resonator Filters for Application in Microwave Integrated Circuits

Design of bandpass filters for microwave integrated circuits (MICS) utilizing dielectric resonators is discussed. Synthesis methods for both Tschebycheff and Butterworth responses are derived. Experimental results with S- and X-band filters are presented, and the agreement between theory and experiments is shown to be fairly good. Limitations on this technique due to poor temperature stability are also discussed.