SMA Extension Cables & SMA Connectors:

An SMA Extension Cable is comprised of coaxial cable with SMA connector at its terminus. A coax cable with SMA connectors can be used to increase the range of cable, antennas and devices. SMA male to SMA female extension cable is widely available and can be used in most applications where SMA connectors are present. Data Alliance provides SMA extension cables in a range of lengths from 6 inches up to 150 feet, but it is important to know that there will be a certain loss of power with each meter of length. There are varieties of coax cables that have been designed to be 'low-loss'. LMR-100, LMR-200, and LMR-300 are double shielded coaxial cables that are very high quality, low-loss coax cable in part because of double-shielding and superior durability, especially in outdoor environments. 

The SMA Connector:  The Sub-Miniature Version A connector, known as the SMA connector is a Radio Frequency (RF) and microwave connector designed to attach antennas to coax cables in a variety of RF applications. As its name describes it is sub-miniature as well as semi-precision and offers a strong and durable 50 ohm impedance connection which can conduct frequencies up to 18GHz and beyond. 

Structure and Component Parts of SMA connectors.

SMA connectors look strikingly similar to F-type coax connectors which are typically found in domestic TV set-ups. They are however structurally distinct and cannot connect with the F-type coax. They are manufactured in brass and stainless steel.

As with other RF connectors the SMA connector is composed of male and female parts which mate to form a secure connection. The connection is threaded at 36 thread per inch and screws down to from a very reliable and well favored union which is rated for 500 mating cycles.

• Male SMA connector has 0.9mm diameter center pin and a barrel with inside threads. Its outer coupling interface has a hex nut which permits tightening with a torque wrench.
• Female SMA connector has a barrel with outside threads that mate with the male connector’s hex-nut. An internal sleeve mates with the male center pin.
• The central pins are supported by a PTFE dielectric in each connector and helps preserve impedance.

SMA Cable Applications

• The sub-miniature size of SMA connectors lends itself to a variety of RF, VHF, UHF and microwave applications.
• Microwave: As it has excellent performance at high operating frequencies, the SMA’s scope enables the development of novel RF antennas that operate at microwave frequencies.
• Hand-held Radio: SMAs are used in Ham radio. They can connect devices such as walkie-talkies to antennas for greater gain and performance. It is also a type of connector used by many DAB aerials.
• Mobile Antennas: A wide range of mobile antennas, particularly magnetic-mounted varieties, are available which feature the SMA connector. The male SMA connector is typically located on the antenna side with the female on the hardware side.
• WiFi: SMA connectors are widely used in WiFi equipment. RP-SMAs were particularly favored to preclude consumer use of antennas which could breach compliance.

SMA Connector Variants:  

1. Right Angled: Data Alliance provides SMA extension cables with right angled SMA connectors and bulkhead fitting SMA connectors.
2. Reverse Polarity or RP-SMA connectors have a structural reversal of the gender of the each connector's contact pin. A Male RP-SAM has a center sleeve within its threaded barrel and a female possess the center pin with an outer threaded barrel.