Calibration and Accuracy in Millimeter Systems. Keith Anderson

Transcription

1 IMS2011 in Baltimore: A Perfect Match Calibration and Accuracy in Millimeter Systems Keith Anderson Agilent Technologies Copyright 2010 Agilent Technologies, Inc.

2 Agenda Interfaces S-parameter calibration Power calibration Accuracy Conclusion Page 2

3 Interfaces Probe On-wafer cal standards Materials / Antenna Free-space cal standards Waveguide Waveguide cal standards Page 3

4 Agenda Interfaces S-parameter calibration Power calibration Accuracy Conclusion Page 4

5 Waveguide Cal Kit Cal kit may include: Short Load Offset load Sliding load Shims (1/4, 1/8 wavelength) Null shims Precision sections Combining standards: Offset short (= Short + Shim) Offset load (= Load + Shim) Line (= Shim) Page 5

6 1-Port Calibration "SOL-style" cals Short / Offset-short / Match (1) Short / Offset-short / Offset-short (1) Where "Match" is either a Load, Offset Load, or Sliding Load. Page 6

7 2-Port Calibration "SOLT-style" cals Short / Offset-short / Match (1) / Thru Short / Offset-short / Offset-short / Thru "TRL-style" cals TRL = Thru / Reflect / Line LRL = Line / Reflect / Line TRM = Thru / Reflect / Match (1) LRM = Line / Reflect / Match (1) (1) Where "Match" is either a Load, Offset Load, or Sliding Load. Page 7

8 Advanced Calibration 2-port "QSOLT" Measure three 1-port standards Measure one zero-length thru Requires four measurements 4-port "QSOLT" Measure three 1-port standards Measure three zero-length thrus Requires six measurements Page 8

9 Agenda Interfaces S-parameter calibration Power calibration Accuracy Conclusion Page 9

10 Calibration Types Source Cal source power & match Set output power Receiver Cal receiver gain & match Measure input power Pout Pin Page 10

11 Calibration Standards iode/thermocouple sensor Waveguide up to 110GHz NIST Traceable Calorimeter-style sensor Waveguide up to 2THz Millimeter head max output Convenient Not traceable Page 11

12 Standard Power Cal Connect power sensor to test port Calibrate source power using sensor Connect source test port to receiver test port Calibrate receiver power using source Page 12

13 Advanced Power Cal Connect power sensor to test port Calibrate one source using sensor Perform S-parameter calibration All sources and receivers are now calibrated Page 13

14 Probe Power Cal isconnect probes Calibrate power at waveguide interface Calibrate S-parameters at waveguide interface Connect probes Calibrate S-parameters at probe tips e-embed S-parameters of probe Page 14

15 Advanced Power Accuracy Receiver leveling VNA measures match at test port Receiver measures source power Software servo's source power Output power is accurate and match-corrected Pout level Software Page 15

16 Agenda Interfaces S-parameter calibration Power calibration Accuracy Conclusion Page 16

17 Measurement Accuracy Random errors Noise Connector repeatability Cable stability rift & Stability errors Receiver Test set Systematic errors Compression & linearity Residual crosstalk Residual calibration errors Page 17

18 Residual Errors Accuracy of standards Load - match Offsets - length, match, loss Waveguide irregularities Burrs Rounded corners & sidewalls Flange edge and surface finish Aperture size Torque Cleanliness Alignment Page 18

19 Alignment Errors Waveguide alignment (connector repeatability) Vertical, horizontal, diagonal and rotational offsets (1) More sensitive at higher frequencies Use precision UG-387 flange (w/ alignment pins) (1) C. Oleson, A. enning, "Millimeter Wave Vector Analysis Calibration and Measurement Problems Caused by Common Waveguide Irregularities", Nov ARFTG Conference igest Page 19

20 1 Waveguide Specifications 6 Waveguide MIL-W-85/3xx Specification for sizes >= WR08 Flange MIL-F-3922/74-00x ("mini-flange") Specification for sizes <= WR08 Lacks precision for sizes <= WR05 Flange MIL-F B (UG387) Specification for sizes >= WR10 Interface tolerance = λ/8 at 325GHz Precision 67B flange for sizes <WR10 Future: IEEE P1785 working group efines bands, apertures, imperfections, flanges Proposed Page 20

21 Traceability S-Parameter cal Traceable to mechanical standards Some MM residual errors are large Power cal Traceable up to 110GHz No industry-wide agreement on traceability above 110GHz Page 21

22 Agenda Interfaces S-parameter calibration Power calibration Accuracy Conclusion Page 22

23 Conclusion MM calibration is available S-parameter cals Power cals - source & receiver There are new, advanced cals QSOLT Power + S-parameter Probe power cal Receiver leveling Accuracy in MM systems is very complex Page 23