What are Multiport Connectors?
Meet the Connector: Multiport Connectors
Multiport connectors integrate multiple coaxial contacts into a single connector module, which achieves higher interconnection density while shortening installation time. Multiport connectors also reduce the form factor and the system’s overall complexity. The choice of multiport connector depends on the required frequency range, signal integrity, and space constraints all necessary considerations when selecting a multiport connector for a specific application. Since multiport RF/coax assemblies have standardized contact cavities, they offer the systemic advantage that, depending upon contact size, RF (coax, duplex, triax, and others), fiber optic modules, and signal contacts (non-RF) can be used in the same connector.
Amphenol SV Microwave’s DC to 40 GHz high-frequency coaxial D38999 contacts allow applications to continue to use the D38999 connector and expand use to include the microwave transmission lines.
In his coverage of IMS2024, David Shaff, director of RF/Microwave at Bishop & Associates, explained that despite the “trend toward multi-port multi-coax assemblies either linear (in a row) or as coax-inserts installed in multi-cavity connectors” and the fact that interfaces for SMPM and SMPS/SMP3 have been standardized, concerns about intermateability due to different coax recess/interfacial depths remain. However, he added, “several suppliers successfully conducted intermateability testing with D38999 assemblies using SMPM interfaces for contact size 16 (and probably larger cavity sizes) involving vibration, etc. Reports are not yet public, but suppliers would be those common to VITA 67 and SOSA. Coaxes for the small size 20 contact cavities (operational to 110 GHz) of MIL-PRF-24308, MIL-DTL-38999 (all four series), and even new MIL-DTL-32689 circulars are considered still as sole source.”
Typical stand-alone multiport coax offered by Radiall.
Several companies including Radiall, Amphenol SV Microwave, Amphenol CIT, Southwest Microwave, SOURIAU (Eaton), and TE Connectivity, offer coax connect assemblies for multiports including circular MIL-STD-38999 or rectangular MIL-DTL-24308 and even ARINC-600 that can be installed by knowledgeable users. Many suppliers such as Samtec, HUBER+SUHNER, and Rosenberger, currently offer multi-ports primarily as preassembled units.
Design Notes
Standards: Multiport connectors used in high-frequency military and avionics systems must meet or exceed the electrical, mechanical, and environmental specifications of the traditional coaxial connectors they are replacing. The use of industry-standard mil-spec connectors as the base design for multi-port connectors has resulted in the adoption of MIL-DTL-38999 connectors for commercial assemblies as well as versions that use standard and custom MIL-DTL-24308 connectors. Multi-housing solutions and those with ganged inserts include stacked Combo-D (with MIL-inserts) and ARINC assemblies.
Mounting: The connector housings are mounted according to non-coax equivalents that differ by connector series. Panel-mounted multiports may have PC termination. (Caution: RF signals usually don’t work well with 90-degree terminations and PCB circuit impedances need to be take into consideration.) Alternatively, they may have lines cabled to other locations on the PCB or to internal components and the electrical performance of these connections need to be understood.
Mating: Multiports mate same as their standard counterparts. This may be by inline blind-mate, rotary coupling, or push-pull. This is a featured benefit as only one connector pair is mated rather than many separate RF connector pairs.
Frequency range: Results will depend upon cable and PCB used, but by themselves, coaxes for multiports are primarily DC to 20 GHz although unique (usually miniaturized) assemblies can perform to 125 GHz with proper assembly and cable.
Impedance: Most multiport connectors have a 50 ohm impedance.
Positions: Multiple sized 2-, 4-, and 6-port board connectors
Ruggedization: Multiport connectors in MIL/Aero applications must withstand high shock and vibration, wide temperature ranges, and function in vacuum-like conditions at high altitudes.
Multiport Quick-Connect Harness with push-on type RF interface from Amphenol CIT is designed to reduce time and cost for the integrator without impacting reliability or performance and supports the same critical operating frequencies, return loss, and RF shielding specifications as heritage single-point threaded interfaces such as SMA and SMK/2.92mm.
Markets and Applications
Military/Aerospace, Datacom/Telecom, Medical, and Industrial
Military and avionics, cable television and internet services, industrial automation, commercial applications for instrumentation and test.
Multiport (M8) and Mini Multiport (MMP) connectors from Times Microwave Systems are high-density interconnect solutions designed for robust performance in extreme environments, meeting MIL-T-81490 and MIL-C-87104 standards. The M8 connector supports frequencies up to 20 GHz, while the MMP extends to 40 GHz. Both feature hermetically sealed housings, spring-loaded interfaces, and jackscrew mating systems for excellent shielding, low insertion loss, and reliability under vibration and temperature stress. Ideal for airborne systems and other high-durability applications.
Suppliers
Multiport connectors are available in many variations from many suppliers, including:
Amphenol CIT, Cinch Connectivity Solutions, Molex, Nicomatic, Radiall, Rosenberger, Samtec, SV Microwave, TE Connectivity, Times Microwave, HUBER + SUHNER, Southwest Microwave, and SOURIAU (Eaton)
Related products
Coax connectors and cables
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