ASTM_D_7449_-_D_7449M_-_22.pdf

Designation:D7449/D7449M22Standard Test Method forMeasuring Relative Complex Permittivity and RelativeMagnetic Permeability of Solid Materials at MicrowaveFrequencies Using Coaxial Air Line1This standard is issued under the fixed designation D7449/D7449M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers a procedure for determiningrelative complex permittivity(relative dielectric constant andloss)and relative magnetic permeability of isotropic,reciprocal(non-gyromagnetic)solid materials.If the material isnonmagnetic,it is acceptable to use this procedure to measurepermittivity only.1.2 This measurement method is valid over a frequencyrange of approximately 1 GHz to over 20 GHz.These limitsare not exact and depend on the size of the specimen,the sizeof coaxial air line used as a specimen holder,and on theapplicable frequency range of the network analyzer used tomake measurements.The size of specimen dimension islimited by test frequency,intrinsic specimen electromagnetismproperties,and the request of algorithm.For a given air linesize,the upper frequency is also limited by the onset of higherorder modes that invalidate the dominant-mode transmissionline model and the lower frequency is limited by the smallestmeasurable phase shift through a specimen.Being a non-resonant method,the selection of any number of discretemeasurement frequencies in a measurement band would besuitable.The coaxial fixture is preferred over rectangularwaveguide fixtures when broadband data are desired with asingle sample or when only small sample volumes areavailable,particularly for lower frequency measurements.1.3 The values stated in either SI units of in inch-poundunits are to be regarded separately as standard.The valuesstated in each system are not necessarily exact equivalents;therefore each system shall be used independently of the other.Combining values from the two systems is likely to result innon conformance with the standard.The equations shown hereassume an e+jtharmonic time convention.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D1711 Terminology Relating to Electrical Insulation3.Terminology3.1 For definitions of terms used in this test method,refer toTerminology D1711.3.2 Definitions:3.2.1 relative complex permittivity(relative complex dielec-tric constant),r*,nthe proportionality factor that relates theelectric field to the electric flux density,and which depends onintrinsic material properties such as molecular polarizability,charge mobility,and so forth:r*5 r2 jr”5DW0EW(1)where:0=permittivity of free spaceDW=electric flux density vector,andEW=electric field vector.1This test method is 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 March 15,2022.Published April 2022.Originallyapproved in 2008.Last previous edition approved in 2014 as D7449/D7449M 14.DOI:10.1520/D7449_D7449M-22.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.13.2.1.1 DiscussionIn common usage the word“relative”is frequently dropped.The real part of complex relativepermittivity(r)is often referred to as simply relativepermittivity,permittivity,or dielectric constant.The imaginarypart of complex relative permittivity(r”)is often referred to asthe loss factor.In anisotropic media,permittivity is describedby a three dimensional tensor.For the purposes of this testmethod,the me