Connector interfaces for the small coaxial line sizes

Transcription

1 Connector interfaces for the small coaxial line sizes National Metrology Institute of Japan Advanced Industrial Science and Technology Masahiro Horibe 1

2 Metrological Standards for S- parameters - Standards: Air dielectric coaxial lines (the wide band frequency) - Lower Freq. limit ~ several ten MHz (depends on the manufacturing limit for line length, e.g. ~ 300 mm) - Higher Freq. limit ~ cut off frequency, spec. PC1.0 Air lines (depends on line size, e.g. Type-N50: ~ 18 GHz, PC1.0: ~ 110 GHz) 2

3 b a Transmission Line Theory - Air Lines Precision unsupported air dielectric coaxial transmission lines Female connector Outer conductor Dielectric (air) Center conductor Male connector 1 b b Z0 ln ln ( ) 2 a a delay [ mm] (ps) 3

4 Calibration Results of Air Line - PC1.0, 16 mm long air line - Dimensional assessments Inner diameter of OC Deformation around connector interface Outer diameter of CC Calibration Capability: PC14, PC7&Type-N50, Type-N75, PC3.5, PC2.92, PC2.4, PC1.85, PC1.0 4

5 Result of Time-domain Band Pass and Dimensional Assessment Time domain TABLE XI: Reflection analysis for mechanical and time-domain Measurements at reflection peaks in 16 mm long air line Peak G (mu) number Electrical Mechanical Difference A A' B B' Peak A Peak B Cause from air line or VNA?? Reflection at B point can NOT separate out from the reflection cause from connector 5

6 Connector Interface Characteristics Electrical and Mechanical Characteristics IEEE 287, IEC standards, MIL standards - Outer conductor inside diameter - Inner conductor outside diameter - Pin-depth - Eccentricity - Male pin diameter - Female Slot effect K connectors However, pin length, female socket structures depend on manufacturers. 6

7 Connector mated interface Characteristic Impedance 50 Ohms 7

8 1.85 mm connectors Maury Agilent Maury Rosenberger Agilent Agilent Rosenberger 8

9 Dimensions around female socket Female Male Male test-port adapter : Agilent ODCC around female socket ODCC(mm) Maury Rosenberger Max Min Max-Min Female socket Reflection coefficient around female socket Reflection Maury Rosenberger Max Min Max-Min Twice 9

10 Test-port (male) Test-port (female) Results of Time-domain Band-pass Reference Plane Measurements Air line Twice Female end Reflection coefficient depends on air line used in evaluation. Note: Reflection coefficient also depends on test-port used in VNA system 10

11 Effect of Air Line Characteristics in Measurement Ripple technique is applied (EA-10/12) to evaluate the residual directivity in VNA A B Region A: 40 GHz to 50 GHz Blue line : d ~ Twice Red line : d ~ Region B: 55 GHz to 65 GHz Blue line : d ~ Twice Red line : d ~ Same in both results Gm d S11 S21S12G Different in both results Here, d < G Depend on air lines 11

12 Summary Difference of interface characteristics of two air line was Twice in the dimensional assessment Twice in the time-domain assessment. Difference of Ripple technique results was TWICE for residual directivity. Further more Same tendency Calibration standards used for VNA (line, offset short, etc.) Transfer standards in metrological traceability Traveling standards used in comparison program are probably in the same situation!! 12

13 Interface issue in comparison program?? Possible problem : Difference > Uncertainty Example Adapter : Manufacturer A G=0.014, U=0.005 Adapter : Manufacturer A Adapter : Manufacturer A G=0.013, U=0.004 Adapter : Manufacturer B Traveling standards G=0.015, U=0.003 Adapter : Manufacturer B? Adapter : Manufacturer C G=0.010, U=0.006 G=0.010, U=0.005 G=0.005, U=0.003

14 Recommendation Recommendations for choosing connectors, i.e. test port adapter s and traveling standard s connectors, used in the microwave and millimeter-wave frequencies are as follows; Low reflection characteristics (low VSWR, low return loss), even if mated interface was made of every connectors, used in precision measurements, as much as possible, Independent of reflection characteristics on geometries of mated connectors, i.e. DUT s and calibration standard s connectors.

15 Issue: Air Hole in female socket 1.85 mm Connector What s kind of effect? Female Male 15

16 Issue: Air Hole in female socket 1.0 mm Connector What s kind of effect? Female Male 16