Design Techniques for High Power RF Coaxial Cable Assemblies

Transcription

1 Design Techniques for High Power RF Coaxial Cable Assemblies Tony Martiniello Chief Technology Officer

2 Primary Considerations Performance Electrical-Mechanical-Environmental Application Prioritizing-Trade-offs Cable-Connector-Attachment Component Design Primary Considerations

3 Typical High Power RF Applications Semiconductor Wafer Fabrication Equipment EMI / RFI Testing Broadcast Aerospace Industrial Equipment Medical Imaging

4 Application Consequences Dielectric material Dielectric Center conductor

5 Performance Assessment / Analysis ELECTRICAL MECHANICAL ENVIROMENTAL Frequency Flexibility Temperature Attenuation Bend Radius Moisture RF Power Size Altitude Shielding Weight Radiation Phase Stability Crush/Pull Strength Fluid Resistance

6 RF Coaxial Cable Design Typical Coaxial Cable Constructions Single shield, extruded (PE) dielectric Double shield, extruded (PE or PTFE) dielectric VP = 66% VP = 66% to 70% Expanded PTFE dielectric, strip & round shields Corrugated Coaxial Cable VP = 76 to 82 VP = 80 to 85

7 Cable Constructions and Power Typical Center Conductor Constructions Solid Stranded (7) Stranded (19) Attenuation Lowest Moderate Highest Power Highest Moderate Lowest Flexibility Lowest Moderate Highest Torque Highest Moderate Lowest Cost Lowest Moderate Highest Typical Dielectric Construction PE PE PTFE PTFE Solid Foamed Solid Expanded Attenuation Best Moderate Low Best VP Lowest Highest Low High Flexibility Lowest Low Moderate Best Temp Low Low Moderate Best Crush Best Low High Moderate Weight High Low Moderate Low Cost Low Low Moderate Highest Typical Jacket Constructions PVC Polyurethane F/G Braid FEP Corrugated Flexibility Good Good Best Good Low Temp Low Low High High High Moisture Good Good Poor Good Good Chemicals Low Low Low High Low Flame Good Low Moderate Good Good Cracking Worst Low N/A Good Low Cost Low Low Highest Moderate Moderate

8 RF Coaxial Cable Reference Guide

9 Cable Power Capabilities

10 Selecting a Connector Interface

11 RF Connector Design Material Selection Common Dielectric - Teflon High Power Options Fluoroloy, BN Construction Mechanical Captivation vs. Epoxy Swept vs. Miter Angles Geometry Line Size Match - Connector & Cable Telescope / Overlap Insulators

12 RF Connector Power Handling

13 Cable / Connector Attachment Design Electrical Matched line size of cable/connector Voltage arc protection Mechanical Pull / torque strength (belt & suspenders) Clamp attachment, TRUtie method Environmental Weather Altitude

14 Summary Application Review Understand as much as possible of actual operating environment or proceed at your own risk Performance Assessment You can t have it all prioritize the must have & nice to have Design Considerations Holistic Design Approach: Cable Connector - Attachment

15 High Power RF Coax Assemblies Conclusion: Proper design considerations can result in a flexible RF cable assembly solution for high power application as high as kw.