The SMA connector was developed in 1960 for the RG-402 semi-rigid cable (0,141 inch). These connectors are designed for 50 ohm resistance and frequency up to 18 GHz (individual precision versions can operate at frequencies up to 26,5 GHz). The SMA connector has a 1 / 4-36 threaded connection, mechanical durability and compact dimensions. The maximum operating frequency for cable connectors depends on the type of wire.
High-frequency SMA-connector has a very wide scope, the key parameters of which are dimensions and cut-off frequency. In phased-array radars, instrumentation, instrument landing systems, as well as other devices that use phase matching, such connectors for coaxial semi-rigid cables, as well as special adapters (plug connectors) are a simple precision means of phase control.
The SMA connector, manufactured in accordance with the requirements of the standard, is compatible with all connectors (regardless of manufacturer) that meet this specification and have the same diameter. They are used in many microwave devices: microstrip and coaxial-wave transitions, attenuators, amplifiers, master oscillators, switches, mixers and filters.
Types of connectors
There are two types of SMA connectors: SMA (“socket” and “plug”) and RP-SMA (also “socket” and “plug”).
In wireless devices (Wi-Fi access point, WiMAX-device, adapter) there is a connector to which the antenna is connected (SMA or N-Type connector). Since this connection consists of two parts, all connectors with a threaded mechanism are two types, paired with each other: sockets and plugs. That is, the latter is screwed into the socket. The terms "mother", "jack" or "female" are used to designate the outlet, and for plug - "male", "plug" or "male".
There are various adapters and adapter cables between different types of connectors.
The second type of connectors are RP-SMA connectors (with reverse polarity or inverse). In such connectors, the opposite is true: the plug has a female contact, but the socket has a plug. Inverse connectors have a modified configuration in the center pin.
By the method of connection, the considered connectors are divided into devices with a threaded and bayonet connection. By way of mounting, connectors are screwed, brazed and crimped. By design, there are instrument, cable, PCB-mounted high-frequency connectors, as well as adapters.
Instrumentation devices are mounted on the housing with a square flange or nut. Cable installation is carried out by soldering or crimping. The connectors mounted on the board are fixed by soldering vertically or horizontally to the surface. Cable connectors are fixed by crimping or soldering. Adapters are used to connect different types of connectors.
In computer technology, SMA connectors are widely used in the organization of antennas Wi-Fi devices. They provide a very reliable contact, and also minimize the losses occurring in the joints. The main characteristics of such connectors - durability and resistance to mechanical loads.