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Free Space Materials Characterization Shelley Blasdel Begley Application Development Engineer Agilent Technologies Agilent Technical Forum Free Space Materials.

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Presentation on theme: "Free Space Materials Characterization Shelley Blasdel Begley Application Development Engineer Agilent Technologies Agilent Technical Forum Free Space Materials."— Presentation transcript:

1 Free Space Materials Characterization Shelley Blasdel Begley Application Development Engineer Agilent Technologies Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 1

2 Agenda What is it? Free Space Measurement Systems Calibration Measurement Results Agilent Technologies Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 2

3 What is Free Space Materials Characterization? Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 3 Measuring Electromagnetic Properties of Materials Using Free Space Measurement Technique. Important for: Circuit design Military Applications Car Radar Applications New Materials Research Incoming Inspection Quality Assurance Health and Safety and more…

4 Electromagnetic Materials Radar Absorbing and Stealth Materials Radome Materials Electronic Substrate and Packaging Materials Specific Absorption Rate (SAR) Phantoms Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 4

5 Transmission Free-Space System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 5 GP-IB or LAN Network Analyzer Sample holder fixtured between two antennae Computer (not required for PNA) 85071E Materials Measurement Software With Option 100 Free Space Calibration

6 Bio-dielectrics: Theories, Mechanisms, Applications, Stamford Hall, Leicester, UK Lightwave Analogy Incident Lens

7 Bio-dielectrics: Theories, Mechanisms, Applications, Stamford Hall, Leicester, UK Lightwave Analogy Incident Reflected Lens

8 Bio-dielectrics: Theories, Mechanisms, Applications, Stamford Hall, Leicester, UK Lightwave Analogy Incident Reflected Lens

9 Bio-dielectrics: Theories, Mechanisms, Applications, Stamford Hall, Leicester, UK Lightwave Analogy Incident Reflected Transmitted Lens

10 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 10 Network Analyzer Block Diagram SOURCE Incident Reflected Transmitted MUT Fixture

11 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 11 Network Analyzer Block Diagram SIGNAL SEPARATION SOURCE Incident Reflected Transmitted MUT Fixture

12 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 12 Network Analyzer Block Diagram RECEIVER / DETECTOR REFLECTED (A) INCIDENT (R) SIGNAL SEPARATION SOURCE Incident Reflected Transmitted MUT Fixture

13 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 13 Network Analyzer Block Diagram RECEIVER / DETECTOR REFLECTED (A) TRANSMITTED (B) INCIDENT (R) SIGNAL SEPARATION SOURCE Incident Reflected Transmitted MUT Fixture

14 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 14 Network Analyzer Block Diagram RECEIVER / DETECTOR PROCESSOR / DISPLAY REFLECTED (A) TRANSMITTED (B) INCIDENT (R) SIGNAL SEPARATION SOURCE Incident Reflected Transmitted MUT Fixture = S11 Incident Reflected Transmitted Incident = S21

15 Transmission Algorithms ( 85071E also has three reflection algorithms) AlgorithmMeasured S-parametersOutput Nicolson-RossS11,S21,S12,S22 r and r Precision (NIST)S11,S21,S12,S22 r FastS21,S12 r

16 Before a Measurement Can be Made… Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 16 Calibration is required!

17 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 17 Thru Reflect Match TRM Calibration Hard to get broadband absorbers for match

18 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 18 TRL Calibration Thru Reflect Line Move the antenna away to compensate for the thickness of the short. Move it back for the next step. Move the antenna away on a quarter-wavelength and then back in the original position. Precise positioning fixtures are expensive

19 Gated Reflect Line (GRL) Calibration Two Tiered Process Two port calibration at waveguide or coax input into antennas removes errors associated with network analyzer and cables. Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 19 ECal, SOLT or TRL Cal done here

20 Gated Reflect Line (GRL) Calibration Two Tiered Process Two additional free space calibration standards remove errors from antennas and fixture. Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 20 Reflect (metal plate of known thickness) Line (empty fixture)

21 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 21 GRL Cal Error Model (forward only) Coax or Waveguide 2-port Cal corrects errors from end of cable back into the instrument. 2-port Cal Terms D MUT Ms Tr Tt Ml 1 S11S22 S21 S12 GRL Error Adapter

22 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 22 GRL Cal Error Model (forward only) Coax or Waveguide 2-port Cal corrects errors from end of cable back into the instrument. 2-port Cal Terms D MUT Ms Tr Tt Ml 1 S11S22 S21 S12 GRL Error Adapter

23 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 23 GRL Cal Error Model (forward only) Coax or Waveguide 2-port Cal corrects errors from end of cable back into the instrument. 2-port Cal Terms D MUT Ms Tr Tt Ml 1 S11S22 S21 S12 GRL Error Adapter

24 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 24 GRL Cal Error Model (forward only) Coax or Waveguide 2-port Cal corrects errors from end of cable back into the instrument. Errors from Antennas and Fixture can be thought of as being lumped into a GRL error adapter. The GRL error adapter is quantified by measurements of reflect and line standards. 2-port Cal Terms D MUT Ms Tr Tt Ml 1 S11S22 S21 S12 GRL Error Adapter

25 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 25 Time Domain of Empty Free Space Fixture Transmitting Antenna Air Receiving Antenna gate

26 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 26 GRL Cal Error Model (forward only) Coax or Waveguide 2-port Cal corrects errors from end of cable back into the instrument. Errors from Antennas and Fixture can be thought of as being lumped into a GRL error adapter. The GRL error adapter is quantified by measurements of reflect and line standards. The original 2-port Cal is modified to correct for the error adapter. 2-port Cal Terms D MUT Ms Tr Tt Ml 1 S11S22 S21 S12 GRL Error Adapter

27 GRL Cal – How it works Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 27 GRL Cal Error Model (forward only) Coax or Waveguide 2-port Cal corrects errors from end of cable back into the instrument. Errors from Antennas and Fixture can be thought of as being lumped into a GRL error adapter. The GRL error adapter is quantified by measurements of reflect and line standards. The original 2-port Cal is modified to correct for the error adapter. 2-port Cal Terms D MUT Ms Tr Tt Ml 1 S11S22 S21 S12 GRL Error Adapter

28 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 28 Free-space X-Band System

29 Free Space 40 – 60GHz System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 29

30 Bio-dielectrics: Theories, Mechanisms, Applications, Stamford Hall, Leicester, UK A Simple Free Space Powder Fixture Powder in Tray Placed Between Antennae Close Up

31 Free Space 75 – 110GHz Standard Gain Horn System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 31

32 Free Space W-band System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 32

33 Free Space GHz Quasi-Optical System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 33

34 Free Space GHz Quasi-Optical System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 34

35 Free Space GHz Quasi-Optical System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 35

36 Free Space GHz Quasi-Optical System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 36

37 Free Space GHz Quasi-Optical System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 37

38 Free Space GHz Quasi-Optical System Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 38

39 Measurement Results Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 39

40 Measurement Results Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 40

41 Conclusion Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 41 Free Space is a useful method for measuring electromagnetic properties of a of materials. Innovative calibration overcomes challenges of previous free space error correction methods.

42 For More Information Visit our website at: Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 42

43 References Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 43 R N Clarke (Ed.), A Guide to the Characterisation of DielectricMaterials at RF and Microwave Frequencies, Published by The Institute of Measurement & Control (UK) & NPL, 2003 J. Baker-Jarvis, M.D. Janezic, R.F. Riddle, R.T. Johnk, P. Kabos, C. Holloway, R.G. Geyer, C.A. Grosvenor, Measuring the Permittivity and Permeability of Lossy Materials: Solids, Liquids, Metals, Building Materials, and Negative-Index Materials, NIST Technical Note Test methods for complex permittivity (Dielectric Constant) of solid electrical insulating materials at microwave frequencies and temperatures to 1650°, ASTM Standard D2520, American Society for Testing and Materials Janezic M. and Baker-Jarvis J., Full-wave Analysis of a Split-Cylinder Resonator for Nondestructive Permittivity Measurements, IEEE Transactions on Microwave Theory and Techniques vol. 47, no. 10, Oct 1999, pg J. Krupka, A.P. Gregory, O.C. Rochard, R.N. Clarke, B. Riddle, J. Baker-Jarvis, Uncertainty of Complex Permittivity Measurement by Split-Post Dielectric Resonator Techniques, Journal of the European Ceramic Society No. 10, 2001, pg Basics of Measureing the Dielectric Properties of Materials. Agilent application note EN, April 28, 2005

44 mm-Wave Free Space Results Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 44 Rexolite expected value e = 2.53

45 Apendix Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 45 Section Title

46 GRL Cal – System Considerations Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 46 Determine Sample Position Determine Sample Size Choose Metal Plate Fixture with Metal Plate Metal Plate

47 GRL Cal - Considerations Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 47 Transmitting Antenna 20nS Receiving Antenna Choose Number of points to Avoid Aliasing Empty Fixture Minumum Number of Points = 1 + Range * (Stop Frequency – Start Frequency) Where Range is the needed alias free range in Seconds

48 GRL Cal - Considerations Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 48 Choose Time Domain Parameters Empty FixtureFixture with Metal Plate Metal Plate at 3.5nS Air at 3.5nS

49 Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 49 Quasi Optical System Schematic Additional information available at :

50 MUT and GRL Error Adapters After 2-Port Calibration Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 50 MUT S11S22 S21 S12 T22T11 T12 T21 O11O22 O21 O12 Six Unknowns 021 = O12 O11 O22 T21 = T12 T11 T22

51 MUT and GRL Error Adapters After O11 and T11 are embedded into the original 2-Port calibration. Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 51 MUT S11S22 S21 S12 T22 T12 T21 O22 O21 O12 Four Unknowns O21 = O12 O22 T21 = T12 T22

52 GRL Metal Plate Standard Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 52 P 11 = P 22 = -1 P 21 =P 12 =0. MUT S11S22 S21 S12 T22 T12 T21 O22 O21 O12

53 GRL Thru Standard (Air) Agilent Technical Forum Free Space Materials Characterization 15 October 2008 Page 53 A 11 =A 22 =0 A 21 = A 12 = = frequency = permittivity of air = permeability of air. d= thickness of the metal plate MUT S11S22 S21 S12 T22 T12 T21 O22 O21 O12


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