Hermetically Sealed Connector vs Standard Connector: What’s The Difference?

Glass-to-Metal Seal

The most common hermetic sealing method for RF connectors. Glass is fused directly to the metal shell and center pin at high temperature, creating a molecular bond that is impervious to gas and liquid at extreme pressures and temperatures.

Ceramic-to-Metal Seal

Used where glass would not provide sufficient dielectric or mechanical strength. Ceramic-to-metal bonds offer excellent stability at high frequencies and are common in microwave and millimeter-wave hermetic feedthrough applications.

Brazed Construction

The glass or ceramic insulator is brazed to the metallic housing using precisely matched thermal expansion coefficients. This prevents micro-cracking across wide temperature cycles from -65°C to +200°C or beyond.

Aerospace and Satellite Systems

Satellites and launch vehicles operate in hard vacuum for years without possibility of maintenance. Any moisture or gas that infiltrates RF connectors causes corrosion of center pins, dielectric absorption, and signal degradation that cannot be corrected in orbit. High frequency hermetic feedthroughs rated for space use must withstand thermal cycling from -180°C to +125°C and outgassing requirements per ASTM E595.

Military-Grade Electronics

Military grade hermetic connectors must pass environmental testing per MIL-STD-810 — covering salt fog, sand and dust, extreme altitude, vibration, and shock. In radar, electronic warfare, and secure communication systems, a corroded or moisture-infiltrated connector can mean mission failure. The investment in hermetic construction pays for itself against the cost of field failures in hostile environments.

Vacuum and Scientific Instruments

RF vacuum feedthrough connectors allow RF signals to pass through the walls of vacuum chambers — in semiconductor manufacturing (ion implanters, sputtering systems), particle accelerators, and analytical instruments — without compromising the internal vacuum. Even a tiny gas leak disrupts processes that depend on pressures below 10⁻⁶ Torr.

Medical Implantable Devices

Cardiac pacemakers, neural stimulators, and cochlear implants use hermetic feedthroughs to pass electrical signals through titanium enclosures into body tissue. The hermetic seal prevents body fluids from reaching internal electronics while simultaneously isolating the body from the device's electrical components — a dual protection requirement that only true hermetic construction can guarantee.

Oil, Gas, and Downhole Sensing

Downhole sensors in oil and gas drilling face pressures exceeding 20,000 psi and temperatures above 175°C. Standard connectors with elastomeric seals fail rapidly under these conditions. Hermetically sealed connectors with glass-to-metal seals maintain full electrical performance and signal integrity at depths and temperatures that destroy conventional designs.

Communication Base Station Equipment

High-power RF connectors on outdoor base station equipment face years of thermal cycling and moisture exposure. While not always requiring full hermetic certification, RF connectors that incorporate glass sintered insulator technology deliver substantially longer service lives than standard PTFE-insulated equivalents in outdoor installations.

Airtight Seal Technology

Hanson's hermetic sealing structures effectively isolate gas and gaseous media, maintaining stable internal environments that prevent gas leakage or contamination across the full product service life.

RF Coaxial Connector Expertise

Main products include RF coaxial connectors, adapters, high-frequency cable assemblies, and low intermodulation cable assemblies — covering standard and hermetic variants across SMA, N-type, TNC, BNC, and other interface series.

Custom Hermetic Solutions

Hanson provides full OEM and custom design services for customers with special hermetic connector requirements, including non-standard flange configurations, multi-pin hermetic feedthroughs, and custom glass formulations.

ISO9001 Quality System

Operating under ISO9001 quality management, Hanson maintains comprehensive product lifecycle traceability and continuously improves manufacturing processes to meet evolving customer requirements in aerospace, defense, and medical markets.

Q1: What is the difference between a hermetic connector and a waterproof connector?

A waterproof connector (IP67/IP68) prevents liquid water ingress under defined test conditions but does not guarantee gas-tight sealing at the molecular level. A hermetically sealed connector creates a quantified airtight barrier — typically verified to a helium leak rate of 1×10⁻⁹ cc/sec or better — that prevents both gas and liquid from crossing the seal interface. Hermetic sealing uses glass-to-metal or ceramic-to-metal fusion, not elastomeric gaskets that degrade over time.

Q2: What does an RF glass sintered sealed insulator do in a hermetic connector?

The glass sintered sealed insulator serves two simultaneous functions: it electrically isolates the center conductor from the outer shell, and it creates the hermetic seal that prevents gas or liquid from passing through the connector body. The glass is fired (sintered) to fuse directly with the metal components, forming a molecular bond that is impervious to gas, moisture, and pressure across extreme temperature ranges.

Q3: Can a hermetic RF connector be used in a vacuum chamber?

Yes — RF vacuum feedthrough connectors are specifically designed for this application. They allow RF signals to pass through the wall of a vacuum vessel while maintaining the internal vacuum. Key considerations include the connector's outgassing rate (materials must meet vacuum cleanliness standards) and the thermal range, since vacuum systems often undergo bake-out cycles at elevated temperatures. Always confirm outgassing data per ASTM E595 when specifying hermetic connectors for vacuum use.

Q4: How are hermetically sealed connectors tested for leak integrity?

The standard method is helium mass spectrometry leak testing per MIL-STD-202 Method 112 or equivalent. The connector is pressurized with helium and placed in a detector chamber; any gas crossing the seal is detected at parts-per-billion sensitivity. This allows quantification of leak rates as low as 1×10⁻¹⁰ cc/sec of helium. Gross leak testing (fluorocarbon bubble test) is used as a screening step before fine leak testing to reject severely defective units efficiently.

Q5: What connector series are available as hermetically sealed versions?

The most common hermetically sealed RF connector series include SMA (DC to 18 GHz), N-type (DC to 11 GHz), TNC, BNC, and 2.92 mm / 2.4 mm for millimeter-wave applications. Multi-pin hermetic feedthroughs are also available for applications requiring combined RF and DC connections through a single sealed header. Custom hermetic connector formats can be manufactured to specific panel or flange dimensions for non-standard enclosure designs.

Q6: Do hermetically sealed connectors affect RF signal quality?

A properly designed hermetic connector has minimal impact on RF performance. The glass insulator introduces a small capacitive discontinuity at the seal interface, which is compensated in the connector's geometry to maintain 50-ohm impedance across the rated frequency band. In long-term outdoor or harsh-environment use, hermetic connectors often show better RF stability than standard connectors because moisture infiltration into the standard connector's dielectric progressively increases insertion loss and VSWR over time.