HomeCoaxialSMA CoaxialGrounded, CF Feedthroughs

Grounded Shield SMA CF Feedthroughs

SMA Coaxial Interface

A 'Subminiature Type-A' coaxial connector, referred to as the SMA coaxial interface, is commonly used in conjunction with high-frequency, low noise 50-ohm instrumentation signal lines. SMA coaxial feedthroughs are constructed in both grounded and floating shield configurations. Floating shield types provide two concentric conductor paths: an outer metal conductor tube (shield) concentric with, and enclosing, a cylindrical center conductor pin. Both paths are electrically isolated from each other and a mounting flange. Grounded shield SMAs provide only one path that's electrically isolated from the flange, where grounded shield and flange are electrically common. Vacuum side of single-ended grounded and floating SMA feedthroughs have a 0.094 inch (2.4-mm) diameter conductor pin that mates with grounded or floating AccuFast™ connectors. Vacuum compatible cable assemblies are fitted with Kapton® insulated 26 AWG, 50-ohm coaxial cable, with either Accufast™ connectors or gold-plated SMA connectors.

Warning — SMAs, with .250-36 thread and .035/.037 pin diameter, are often mistaken for Microdot  S-93, connectors with .250-32 threads and .030/.033 pins. To avoid possible damage to one or both connector interfaces, these connectors should never be cross-mated. Compare Microdot ® and SMA differences below...

Thread Size ComparisonCF Flange Interface

Features

  • SMA Coaxial Interface
  • Grounded and Floating Shield
  • Single and Double Ended configurations
  • Kapton® insulated 50-Ohm cables
  • High temperature rated to 250°C
  • UHV compatible construction
  • Conflat® and ISO KF compatible mounts
  • Air service cables / connectors
  • Custom solutions on request
     

Specifications

Electrical 
Voltage 1, Maximum 
   Grounded Shield700 VDC
   Floating Shield700 VDC
   Current, Max @ 20°C1 A
   Impedance2, Nominal50 Ohms
   Frequency2, Nominal6 GHz
Material 
Shell304 Ss
Pin / Conductor304 Ss
Insulation, CeramicAlumina
Connector, Vacuum 3 
   AccuFast™PEEK / Ss
   SMA (Au plated)PEEK / Brass
Connector, AirTeflon®
Cable Insulation (Type F Film)Kapton®
Vacuum Range 
UHV, Ultrahigh vacuum1x10E-10 Torr
HV, High vacuum1x10E-8 Torr
Temperature Range4 
Feedthrough, Single Ended250°C
Flange, Conflat®450°C
Flange, ISO150°C
Connector / Cable, Air165°C
Connector / Cable, UHV250°C
Thermal Gradient, Maximum25°C/minute
Notes 
  1. Electrical ratings are maximum test values, with feedthrough's vacuum side at ≤ 1x10-4 Torr. Feedthroughs are intended for instrumentation applications carrying low level signal voltage/current.
  2. Impedance and frequency ratings may vary with the type of interface cables and connectors used.
  3. PEEK is a polyether ether ketone thermoplastic.
  4. Overall assembly ratings must be adjusted to that of its lowest rated component. For cryogenic service, the lowest recommended temperature is -200°C
  5. Connectors and cables are not included with feedthrough and must be purchased separately.