5 Mins Guide Of What SMA Connector Is And Used For
SMA (Sub Miniature version A) connectors are most widely used coaxial RF connectors nowadays. The small size, outstanding durability and reliable performance make SMA connector favorite choice for RF engineers.
In the following, we would like to provide the insight of SMA connectors and indicate features of Chin Nan's SMA connectors.
Table of content:
Introduction
SMA connectors feature an impedance of 50 Ω and a 1/4-inch diameter, 36-thread-per-inch threaded interface with a screw-on coupling mechanism.
MIL-STD-348B of Chin Nan
Chin Nan SMA connectors are built in accordance with MIL-STD-348 interface which latest version is MIL-STD-348B. Besides conforming to the interface, Chin Nan upgrades the performance for MIL-STD-348B connectors in the meantime.
There are several high frequency connectors which apply the same outside thread as SMA could potentially mate with SMA connectors, such as 3.5 mm connector, frequency rated to 34 GHz and 2.92 mm connector, frequency rated to 40 GHz.
SMA 27GHz Connectors
SMA connectors operate up to 18 GHz, but in order to respond to the growth of the communication system, there is an extended version that operates up to 27 GHz for higher frequency applications.
SMA 27GHz Connectors
Chin Nan SMA 27 GHz connectors feature stainless steel construction and passivated or gold plating.
They maintain the same mechanical characteristics and are able to mate with standard SMA connectors.
Chin Nan offers an extensive line of SMA receptacles and cable connectors for semi-rigid and flexible coaxial cables.
SMA has a wide range of applications, such as telecommunications, wireless communications, measurement, and microwave systems (filters, attenuators, and oscillators). Besides, Chin Nan provides various solutions such as non-magnetic, sealed and reverse-polarity in SMA series.
What Is 3.5 mm Connectors
SMA was designed to be an economical miniaturized system connector. It was designed to be used in semi-rigid cable assemblies and the parts not needing repeated connection or disconnection.
SMA is not a precision connector used in the laboratory. It has limited number of connection cycles in the measurement and calibration applications. Its durability only rated for 500 times of connect/disconnect operations.
The 3.5 mm connector, which utilizes air dielectric for higher frequency is a precision connector known for its durability. 3.5 mm was designed as the test connector for the network analyzer operating at higher frequency up to 34GHz.
What Is 2.92 mm Connectors
SMA 2.92mm Connectors
2.92 mm, also known as K, SMK or K type, are designed with SMA footprint to provide the connector performance up to 40 GHz in 1970's.
2.92 mm connectors feature an air dielectric for higher frequency operating in the range DC to 40 GHz. The 2.92 mm male connector is designed with a shorter center contact in order to prevent the damage happened while mating.
2.92 mm connectors have excellent performance and are also mechanically compatible to SMA and 3.5 mm connectors. Those advantages make 2.92mm connectors quickly recognized by the majority of manufacturers. 2.92mm became one of the most widely used millimeter wave connectors in the world.
Chin Nan has the expertise to design and build 2.92mm connectors for semi-rigid cable assemblies, 2.92mm receptacles, four hole flange and 2.92mm precision adapters to satisfy various demands.
SMA Series Comparison
The outer diameter of SMA and SMA 27 GHz connectors is about 4.13 mm. The outer diameter of the other 2 connectors is 3.5 mm and 2.92 mm.
The major difference between 3.5mm and standard SMA is the dielectric material: 3.5mm uses air. The outer contact of 3.5mm is thicker than SMA so the mechanical performance of 3.5mm connectors is also better than SMA connectors.
The electrical performance, durability and reputability of 3.5mm connector are better than SMA. Therefore, 3.5mm is much more suitable to apply to the measurement or calibration device or industries.
The difference between 2.92mm and SMA is that the 2.92 mm male center contact is shorter than SMA or 3.5mm. This ensures the outer conductor of the male and female connectors engage before the center contacts mate.
The 2.92mm connectors can mate with SMA and 3.5mm connectors, but it has higher electrical performance and operating frequency in virtue of its air dielectric feature and smaller inside diameter of the respective outer conductor.
It would be ideal to use air as insulator for performance but we still need some kind of materials that will hold the center contact of the connector in place and help dielectric constant. SMA 27 GHz connectors will be the option for operating as higher frequency with PTFE dielectric.
