1、Designation: D5568 08D5568 14Standard Test Method forMeasuring Relative Complex Permittivity and RelativeMagnetic Permeability of Solid Materials at MicrowaveFrequencies Using Waveguide1This standard is issued under the fixed designation D5568; the number immediately following the designation indica
2、tes the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a procedure for det
3、ermining relative complex permittivity (relative dielectric constant and loss) andrelative magnetic permeability of isotropic, reciprocal (non-gyromagnetic) solid materials. If the material is nonmagnetic, it isacceptable to use this procedure to measure permittivity only.1.2 This measurement method
4、 is valid over a frequency range of approximately 100 MHz to over 2040 GHz. These limits arenot exact and depend on the size of the specimen, the size of rectangular waveguide transmission line used as a specimen holder,and on the applicable frequency range of the network analyzer used to make measu
5、rements. The practical lower and upperfrequencies are limited by specimen dimension requirements (large specimens at low frequencies and small specimens at highfrequencies). size of specimen dimension is limited by test frequency, intrinsic specimen electromagnetism properties, and therequest of alg
6、orithm. Being a non-resonant method, the selection of any number of discrete measurement frequencies in ameasurement band would be suitable. Use of multiple rectangular waveguide transmission line sizes are required to cover thisentire frequency range (100 MHz to 2040 GHz). This test method can also
7、 be generally applied to circular waveguide test fixtures.The rectangular waveguide fixture is preferred over coaxial fixtures when samples have in-plane anisotropy or are difficult tomanufacture precisely.1.3 The values stated in SI units are to be regarded as the standard. The values given in pare
8、ntheses are in English units.inch-pound units and are included for information only. The equations shown here assume an e+jt harmonic time convention.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this
9、 standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1711 Terminology Relating to Electrical Insulation3. Terminology3.1 For other definitions used in this test method, refer t
10、o Terminology D1711.3.2 Definitions:3.2.1 relative complex permittivity (relative complex dielectric constant), r*, nthe proportionality factor that relates theelectric field to the electric flux density, and which depends on intrinsic material properties such as molecular polarizability, chargemobi
11、lity, etc.:and so forth:r*5r 2jr 5 DW0EW(1)1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.12 on Electrical Tests.Current edition approved Dec. 15, 2008Nov. 1, 2014. Published Jan
12、uary 2009November 2014. Originally approved in 1994. Last previous edition approved in 20012008as D5568 01.D5568 08. DOI: 10.1520/D5568-08.10.1520/D5568-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM
13、 Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically pos
14、sible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCo
15、pyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1where:0 = the permittivity of free space,D = the electric flux density vector, andE = the electric field vector.3.2.1.1 DiscussionIn common usage the word “relative” is frequently dropped.
16、 The real part of complex relative permittivity (r) is often referredto as simply relative permittivity, permittivity, or dielectric constant. The imaginary part of complex relative permittivity (r) isoften referred to as the loss factor. In anisotropic media, permittivity is described by a three di
17、mensional tensor.3.2.1.2 DiscussionFor the purposes of this test method, the media is considered to be isotropic, and thereforeisotropic and, therefore, permittivity isa single complex number at each frequency.3.2.2 relative complex permeability, r*, nthe proportionality factor that relates the magn
18、etic flux density to the magnetic field,and which depends on intrinsic material properties such as magnetic moment, domain magnetization, etc.:and so forth:r*5r 2jr 5 BW0HW(2)where:0 = the permeability of free space,B = the magnetic flux density vector, andH = the magnetic field vector.3.2.2.1 Discu
19、ssionIn common usage the word “relative” is frequently dropped. The real part of complex relative permeability (r) is often referredto as relative permeability or simply permeability. The imaginary part of complex relative permeability (r“) is often referred toas the magnetic loss factor. In anisotr
20、opic media, permeability is described by a three dimensional tensor.3.2.2.2 DiscussionFor the purposes of this test method, the media is considered to be isotropic, and therefore permeability is a single complex numberat each frequency.3.3 Definitions of Terms Specific to This Standard:3.3.1 A list
21、of symbols specific to this test method is given in Annex A1.3.3.2 calibration, na procedure for connecting characterized standard devices to the test ports of a network analyzer tocharacterize the measurement systems systematic errors. The effects of the systematic errors are then mathematically re
22、movedfrom the indicated measurements. The calibration also establishes the mathematical reference plane for the measurement test ports.3.3.2.1 DiscussionModern network analyzers have this capability built in. There are a variety of calibration kits that can be used depending on thetype of test port.
23、 The models used to predict the measurement response of the calibration devices depends on the type of calibrationkit. Most calibration kits come with media that can be used to load the definitions of the calibration devices into the networkanalyzer. Calibration kit definitions loaded into the netwo
24、rk analyzer must match the devices used to calibrate. Since bothtransmission and reflection measurements are used in this standard, a two-port calibration is required.3.3.3 network analyzer, na system that measures the two-port transmission and one-port reflection characteristics of amultiport syste
25、m in its linear range and at a common input and output frequency.3.3.3.1 DiscussionD5568 142For the purposes of this standard, this description includes only those systems that have a synthesized signal generator, and thatmeasure the complex scattering parameters (both magnitude and phase) in the fo
26、rward and reverse directions of a two-port network(S11, S21, S12, S22).3.3.4 scattering parameter (S-parameter), Sij,na complex number consisting of either the reflection or transmission coefficientof a component at a specified set of input and output reference planes with an incident signal on only
27、 a single port.3.3.4.1 DiscussionAs most commonly used, these coefficients represent the quotient of the complex electric field strength (or voltage) of a reflectedor transmitted wave divided by that of an incident wave. The subscripts i and j of a typical coefficient Sij refer to the output andinpu
28、t ports, respectively. For example, the forward transmission coefficient S21 is the ratio of the transmitted wave voltage atReference Plane 2 (Port 2) divided by the incident wave voltage measured at Reference Plane 1 (Port 1). Similarly, the Port 1reflection coefficient S11 is the ratio of the Port
29、 1 reflected wave voltage divided by the Port 1 incident wave voltage at referenceplane 1 (Port 1).3.3.5 transverse electric (TEmn) wave,nan electromagnetic wave in which the electric field is everywhere perpendicular to thedirection of propagation.3.3.5.1 DiscussionThe index m is the number of half
30、-period variations of the field along the waveguides larger transverse dimension, and n is thenumber of half-period variations of the field along the waveguides smaller transverse dimension. The dominant wave in arectangular waveguide is TE10. The electric field lines of the TE10 mode are parallel t
31、o the shorter side.3.3.6 cutoff frequency, nthe lowest frequency at which non-evanescent, dominant mode propagation can occur within arectangular waveguide.4. Summary of Test Method4.1 A carefully machined test specimen is placed in an electromagnetic waveguide transmission line and connected to aca
32、librated network analyzer that is used to measure the S-parameters of the transmission line-with-specimen. A specifieddata-reduction algorithm is then used to calculate permittivity and permeability. If the material is nonmagnetic a different algorithmis used to calculate permittivity only. Error co
33、rrections are then applied to compensate for air gaps between the specimen and thetransmission line conductor surfaces.5. Significance and Use5.1 Design calculations for radio frequency (RF), microwave, and millimetre-wave components require the knowledge of valuesof complex permittivity and permeab
34、ility at operating frequencies. This test method is useful for evaluating small experimentalbatch or continuous production materials used in electromagnetic applications. Use this method to determine complex permittivityonly (in non-magnetic materials)materials), or both complex permittivity and per
35、meability simultaneously.6. Interferences6.1 The upper limits of permittivity and permeability that can be measured using this test method are restricted by thetransmission line and specimen geometries, which can lead to unwanted higher order waveguide modes. In addition, excessiveelectromagnetic at
36、tenuation due to a high loss factor within the test specimen can prevent determination of permittivity andpermeability. No specific limits are given in this standard, but this test method is practically limited to low-to-medium values ofpermittivity and permeability.6.2 The existence of air gaps bet
37、ween the test specimen and the transmission line introduces a negative bias into measurementsof permittivity and permeability. In this test method compensation for this bias is required, and to do so requires knowledge of theair gap sizes. Air gap sizes are estimated from dimensional measurements of
38、 the specimen and the specimen holder, which can bemeasured with micrometers, feeler gauges, or other precision instruments. Several different error correction models have beendeveloped, and a frequency independent series capacitor model is described in AnnexA2.Air gap corrections are only approxima
39、teand therefore this test method is practically limited to low-to-medium values of permittivity and permeability.7. Apparatus7.1 Experimental Test FixtureThe test fixture includes a specimen holder connected to a network analyzer, as shown in Fig.1.7.2 Network AnalyzerThe network analyzer needs a fu
40、ll 2-port test set that can measure transmission and reflection scatteringparameters. Use a network analyzer that has a synthesized signal generator in order to ensure good frequency stability and signalpurity.D5568 1437.3 Waveguide Calibration KitTo define Port 1 and Port 2 measurement reference pl
41、anes, calibration of the waveguide testfixture is required.Acalibration kit consists of well-characterized standard devices and mathematical models of those devices. Usea through-reflect-line (TRL), an open-short-load-through (OSLT), or any other calibration kit that yields similar calibration quali
42、tyto calibrate the waveguide test fixture.7.4 Specimen Holder:7.4.1 Because parameters such as specimen holder length and cross-sectional dimensions are of critical importance to thecalculation of permittivity and permeability, carefully measure and characterize the physical dimensions of the specim
43、en holder.7.4.2 If a separate length of transmission line is used to hold the specimen, ensure that that empty length of line is also in placeduring calibration of the specimen holder.7.4.3 The theoretical model used for this test method assumes that only the dominant mode of propagation exists (TE1
44、0 forrectangular waveguide or TE11 for circular waveguide). The existence of higher-order modes restricts the measurable bandwidthfor a given waveguide test fixture.7.4.4 Be sure that the specimen holder dimensions are within proper tolerances for the waveguide transmission line size in use.For an X
45、-band rectangular waveguide transmission line, the dimensions of the inner opening are denoted by “a” the width and “b”the height. Proper tolerances are then:X-band waveguide width:a 522.8660.10 mm 0.90060.004 in.! (3)X-band waveguide height:b 510.1660.10 mm 0.90060.004 in.! (4)7.4.4.1 Dimensions an
46、d tolerances of other standard waveguides are in the appropriate manufacturers specifications and U.S.military specifications.38. Test Specimen8.1 Make the test specimen long enough to ensure good alignment inside the holder. Also, make the test specimen long enoughto ensure that the phase shift thr
47、ough the specimen is much greater than the phase measurement uncertainty of the network analyzerat the lowest measurement frequency. If a specimen is expected to have low loss, sufficient length is also required to ensureaccurate determination of the loss factor. Finally, for high loss specimens, th
48、e specimen length cannot be so long that high insertionloss prevents material property inversion.8.2 Accurately machine the specimen so that its dimensions minimize the air gap that exists between the conductor surfaces andthe specimen. In this respect, measure the specimen holders dimensions in ord
49、er to specify the tightest tolerances possible forspecimen preparation. Keep physical variations of specimen dimensions as small as is practicable and include specimendimensions and uncertainties in the report.3 MIL-DTL-85/1F, 20 November 1998.FIG. 1 Diagram of Experimental FixtureD5568 1449. Preparation of Apparatus9.1 Inspect Network Analyzer Test PortsInsure that the recession of both test ports center conductor shoulder behind the outerconductor mating plane meets the minimum specifications. Refer to network analy
