D38999 Twinax & Quadrax Contacts

Amphenol Military & Aerospace D38999 Twinax & Quadrax contacts provide shielded, high‑speed data connectivity within standard MIL‑DTL‑38999 circular connectors. They enable engineers to route differential‑pair and broadband signals through existing connector layouts without separate RF interfaces, simplifying mixed‑signal and hybrid harness designs.

Technical Overview

The Twinax contact carries balanced twinaxial signals through a common shield, minimizing magnetic and electrostatic coupling and maintaining shielding integrity through the entire connector assembly. This design protects against external interference and supports applications requiring reliable data transfer under harsh EMI or EMP exposure. The Quadrax contact groups four conductors into two matched impedance pairs, typically 100 Ω or 150 Ω, for gigabit‑rate differential transmission.

Integration and Compatibility

• Fits standard MIL‑DTL‑38999 cavity sizes 4, 8, 12, and 16.
• Interchangeable with power or signal contacts within mixed‑signal connector arrangements.
• Available in crimp and PCB‑termination styles for harness or board‑level assembly.
• Accepts common RG‑type and commercial twinax or coax cables.

Performance and Shielding

Both Twinax and Quadrax designs feature continuous 360° shield termination, ensuring low EMI emission and high noise immunity. When integrated within sealed D38999 shells, they benefit from the connector’s grommets, environmental sealing, and mechanical retention, delivering ruggedized signal integrity for mission‑critical architectures.

Typical Applications

• Avionics and mission computers using Ethernet, Fibre Channel, or ARINC data buses.
• Defense communications and sensor systems requiring EMI/EMP shielding.
• Rugged airborne, naval, and ground‑vehicle harness assemblies.

Selection Guidance

Engineers choose Twinax contacts when balanced transmission and magnetic interference control are primary requirements, and Quadrax contacts when multi‑pair high‑speed differential channels are needed within a single cavity. Both types support mixed‑signal connector layouts, enabling optimized space, weight, and bandwidth balance in MIL‑Spec harness architectures.