What is A Blind Mate RF Connector?
Peter McNeil | Sep 05, 2024
Many RF engineers are familiar with the standard threaded coaxial connector that range in sizes from several centimeter to sub-millimeter diameters. For some of the standard types of coaxial connectors and specialized versions there are also Blind-Mate RF Connectors, which are made for scenarios where mating with threaded or bayonet types of connections may be difficult or impossible. Blind-mate connectors also differ from spring-contact type connectors as well, as blind-mate connectors include some type of alignment and retention mechanisms to ensure a consistent and reliable connection.
Blind-mate refers to making a coaxial connection by sliding or pushing two compatible connectors together where a retention mechanism and alignment features establish a coaxial connection that meets specification for that connector type. These connectors typically don’t require tooling, though some type of fixturing or extra alignment tools may be useful for a technician making large numbers of blind mate connections or if the blind mate connectors are very small. An example of this is using blind mate connectors in a ganged configuration with a fixture housing that functions as a multi-conductor cable assembly. This can be extremely useful for high-density interconnect situations from board-to-board or cable-to-board.
Blind-mate connectors typically offer more reliable connection than spring-force contact style RF Connectors
(such as pogo pins) in rugged applications where the forces could easily separate a connection and cause wear for spring contacts. This is because blind-mate connectors are often designed to captivate the center conductor and use multiple points of retention to ensure good outer conductor contact along the entire diameter of the outer conductor. In this way, blind-mate connectors can also provide better shielding than spring-force contacts. Mating or cycling the connection of blind-mate connectors is more difficult and involved than spring-force contacts but can still reliably be done over many thousands of cycles depending on the design of the blind-mate connector.
This is why blind-mate connectors are now often used in automated testing of RF systems and high-speed digital systems. There is a general legacy rule-of-thumb that blind-mate connectors can’t achieve the same level of repeatability as threaded coaxial connectors. For a human operator making the connection, this is likely true. However, there is evidence that an automated system can mate blind-mate connectors to a similar if not superior level to threaded coaxial connectors. This is significant because there are now blind-mate coaxial connectors that reach millimeter-wave frequencies, where automated testing has previously been difficult or expensive. In order to bring down costs of millimeter-wave systems, reliable and repeatable automated testing connections are extremely valuable.