D38999 Coaxial Cable Contacts

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Amphenol Military & Aerospace D38999 Coaxial Cable Contacts are specialized RF inserts that extend the capability of MIL‑DTL‑38999 circular connectors to carry high‑frequency signals alongside digital and power lines in one shell. These coaxial contacts are standard components across Amphenol’s mixed‑signal D38999 portfolio and support broadband operation through Microwave and mmWave ranges when paired with validated inserts and cabling systems.

Functional Overview

Each contact functions as a controlled‑impedance 50 Ω transmission line comprising inner and outer conductors separated by a dielectric insulator. Precision geometry and tight dimensional tolerances optimize impedance match and minimize VSWR across the operating bandwidth. When installed in MIL‑DTL‑38999 Series I–III shells, they create a sealed, shielded RF channel within standardized mixed‑signal connector layouts.

Design Features and Options

• Available for standard cavity sizes 8, 12, 16, and 20 to accommodate multiple RF interface diameters and power levels.
• Compatible with SMP, SMPM, SMPS, and other 50 Ω interface families depending on size and series selection.
• Offered in floating‑mount and spring‑loaded configurations to maintain alignment and consistent VSWR under vibration and thermal stress.
• Employ Durmalon or black zinc‑nickel RoHS‑compliant plating for corrosion resistance and EMI continuity.
• Manufactured and audited under Amphenol’s coaxial contact frequency validation and dimensional inspection workflows to verify impedance continuity and mechanical fit.

Integration and Application Guidance

Coaxial cable selection and precise cable‑to‑contact impedance matching are critical for achieving maximum bandwidth and minimal reflection. These contacts can be combined with power, signal, twinax, or quadrax variants to create compact hybrid layouts suited for radar, EW, and high‑speed avionics networks. Engineers should match contact size to intended frequency range and cable diameter to ensure proper fit and return‑loss performance.

Typical Use Cases

• Microwave sensor and radar feedlines within Series III and Micro38999 connectors
• SATCOM uplink and downlink assemblies requiring controlled 50 Ω paths
• Mixed‑signal harnesses combining RF, data, and power for aerospace platforms
• Open‑architecture modules conforming to SOSA and VITA‑aligned mechanical layouts

Quality Assurance and Audit Process

Every contact style follows Amphenol’s coaxial contact frequency validation procedure—a broadband return‑loss measurement and dimensional inspection sequence confirming impedance uniformity and mechanical stability. This auditing ensures that each contact performs reliably under vibration, temperature cycling, and repeated mating cycles typical of defense and aerospace operations.