Four coaxial connectors are commonly used in aerospace, military, and industrial applications, containing four conductors arranged in a four channel configuration within a single connector housing, designed to transmit high-speed Ethernet or other differential signals with minimal crosstalk.
Quadrax connectors have evolved from a broader category of coaxial and triaxial connector technologies aimed at improving signal transmission and reducing interference in high-speed data applications. Companies including Amphenol and TE Connectivity have played an important role in improving and commercializing quad coaxial designs to meet the aerospace and military demand for robust high-frequency connectors. These companies have contributed to the development of the four core configuration, which enables differential signal pairs to be transmitted with low crosstalk, laying the foundation for the four core connectors we see today.
There are many industry standards covered Quadrax connector.
MIL-DTL-38999： The military standard for circular connectors includes specifications for four coaxial contacts, ensuring that the four coaxial connectors used in these systems meet strict requirements for durability, environmental sealing, and electromagnetic compatibility (EMC).
ARINC 600 and ARINC 404: These aerospace standards outline the requirements for quad coaxial connectors used in avionics, particularly for high-speed data transmission in commercial aircraft.
IEEE 802.3： In applications such as Ethernet, IEEE standards apply to the electrical characteristics of differential pairs within four coaxial connectors to ensure compliance with data protocols such as 1000BASE-T (Gigabit Ethernet).
Installation type or type: panel installation, cable installation, or PCB installation
Location: Quadrax connectors typically have four conductors within a single contact, arranged in a four channel configuration (two pairs) for differential signals such as Ethernet or high-speed data lines. In circular connectors, such as those based on MIL-DTL-38999, the four coaxial contacts can be placed within a multi position housing, allowing for the use of multiple four coaxial contacts in a single connector housing.
Pin: Each Quadrax contact of a Quadrax connector typically has four pins arranged in a square or diamond pattern. These four pins consist of two differential pairs (two positive pins and two negative pins), designed to transmit high-speed data signals with minimal crosstalk.
In circular connectors, such as those following the MIL-DTL-38999 standard, multiple quad coaxial contacts can be installed in a single housing, allowing for multiple quad coaxial connections within a connector body.
Contact resistance: The contact resistance of a four coaxial connector should be less than 5 milliohms (m Ω) per contact.
Pitch: Typically, the pin spacing within each four coaxial contact is very close, with a center to center distance of approximately 1.27 millimeters (0.05 inches).
Height: The height of each individual pin within the contact is typically around 3.5 millimeters to 5 millimeters (0.14 to 0.20 inches), but may vary depending on the contact type and connector size.
Contact resistance: The contact resistance of a four coaxial connector should be less than 5 milliohms (m Ω) per contact.
Material specifications: Reinforcing materials help ensure the performance, reliability, and service life of four coaxial connectors, especially in harsh environments such as aerospace, military, and high-speed data applications. The casing is typically made of thermoplastic or thermosetting polymers, such as polyamide (nylon) or PBT (polybutylene terephthalate), for general applications.
For harsh or high-performance environments, the casing can be made of aluminum (usually coated with chromate or anodized aluminum) or stainless steel to enhance durability and environmental resistance.
Electrical characteristics
Voltage AC/DC: For military grade or high-performance quad coaxial connectors, the rated voltage is typically around 250-500 V (volts) AC or DC, but this may vary depending on the manufacturer and specific application.
For low voltage, high-speed data transmission applications (such as Ethernet), the rated voltage may be lower, typically around 50-150 V.
Current (Ampere): The rated current of most four coaxial connectors is typically 3 A to 10 A per contact. Some four coaxial connectors are designed specifically for high current applications, with each contact capable of carrying up to 20 A or higher current, especially for connectors used in power transmission or industrial applications.
Market and Applications
Military and aerospace, transportation, industry, automotive, data communication and telecommunications, medical, testing and measurement
Quadrax connectors are commonly used in military and aerospace electronic systems; In radar, sonar, and other sensor systems; Satellite communication and space exploration; In telecommunications equipment; Energy and power generation; Medical imaging, robotics and wearable devic
