ASTM_D_2520_-_13.pdf

Designation:D252013Standard Test Methods forComplex Permittivity(Dielectric Constant)of Solid ElectricalInsulating Materials at Microwave Frequencies andTemperatures to 1650C1This standard is issued under the fixed designation D2520;the number immediately following the designation indicates 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.Scope1.1 These test methods cover the determination of relative(Note 1)complex permittivity(dielectric constant and dissipa-tion factor)of nonmagnetic solid dielectric materials.NOTE1The word“relative”is often omitted.1.1.1 Test Method A is for specimens precisely formed to theinside dimension of a waveguide.1.1.2 Test Method B is for specimens of specified geometrythat occupy a very small portion of the space inside a resonantcavity.1.1.3 Test Method C uses a resonant cavity with fewerrestrictions on specimen size,geometry,and placement thanTest Methods A and B.1.2 Although these methods are used over the microwavefrequency spectrum from around 0.5 to 50.0 GHz,each octaveincrease usually requires a different generator and a smaller testwaveguide or resonant cavity.1.3 Tests at elevated temperatures are made using specialhigh-temperature waveguide and resonant cavities.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2A893/A893M Test Method for Complex Dielectric Constantof Nonmetallic Magnetic Materials at Microwave Fre-quenciesD150 Test Methods for AC Loss Characteristics and Permit-tivity(Dielectric Constant)of Solid Electrical InsulationD1711 Terminology Relating to Electrical Insulation3.Terminology3.1 Definitions of Terms.For definitions of terms used inthis test method,refer to Terminology D1711.3.2 Definitions of Terms Specific to This Standard:3.2.1 neper,na division of the logarithmic scale whereinthe number of nepers is equal to the natural logarithm of thescalar ratio of either two voltages or two currents.NOTE2The neper is a dimensionless unit.1 neper equals 0.8686 bel.With Ixand Iydenoting the scalar values of two currents and n being thenumber of nepers denoted by their scalar ratio,then:n 5 lnelx ly!where:lne=logarithm to base e.3.2.2 For other definitions used in these test methods,referto Terminology D1711.4.Significance and Use4.1 Design calculations for such components as transmis-sion lines,antennas,radomes,resonators,phase shifters,etc.,require knowledge of values of complex permittivity at oper-ating frequencies.The related microwave measurements sub-stitute distributed field techniques for low-frequency lumped-circuit impedance techniques.4.2 Further information on the significance of permittivity iscontained in Test Methods D150.4.3 These test methods are useful for specificationacceptance,service evaluation,manufacturing control,andresearch and development of ceramics,glasses,and organicdielectric materials.TEST METHOD ASHORTED TRANSMISSIONLINE METHOD5.Scope5.1 This test method covers the determination of microwavedielectric properties of nonmagnetic isotropic solid dielectric1These test methods are under the jurisdiction of ASTM Committee D09 onElectrical and Electronic Insulating Materials and is the direct responsibility ofSubcommittee D09.12 on Electrical Tests.Current edition approved May 1,2013.Published August 2013.Originallyapproved in 1966.Last previous edition approved in 2001 as D252001 which waswith drawn in 2010 and reinstated in May 2013.DOI:10.1520/D2520-132For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 materials in a shorted transmission line method.This testmethod is useful over a wide range of values of permittivityand loss(1).3It is suitable for use at any frequency wheresuitable transmission lines and measuring equipment are avail-able.Transmission lines capable of withstanding temperaturesup to 1650C in an oxidizing atmosphere can be used to holdthe specimen.6.Summary of Test Method6.1 For an isotropic dielectric medium,one of Maxwellscurl equations is writtencurl H 5 j*0E(1)assuming exp(jt)time dependence,where:*=relative complex permittivity,0=(absolute)permittivity of free space,and=2f,f being the frequency.The notation used will be as follows:*5 2j 5 1 2 j tan!(2)where:tan=/,=real part,and=imaginary part.The value of*is obtainable from observations that evaluatethe attenuation and