SMA Knowledge

The full name of SMA is Small A Type. It is a typical microwave high frequency connector. The highest frequency used is 18GHz. In the design of radio frequency circuits, SMA connectors are often added to the circuit for input and output signals. SMA connectors are the most common connectors in radio frequency circuits.
SMA overview
SMA, a common antenna interface:

SMA is the abbreviation of Sub-Miniature-A. The full name of the antenna interface of SMA should be SMA inverse male. ). The wireless devices with this interface are the most popular. APs with more than 70%, wireless routers and wireless network cards with more than 90% PCI interfaces all use this interface. This interface is moderate in size, and there are also devices such as handheld walkie-talkies. Many of them are of this type, but the needles and tubes inside are opposite to the wireless devices. Wireless APs and wireless routers using this interface include most of the civilian equipment. TP-LINK, DLINK, Netgear, Belkin and other brands, as long as the antenna is detachable, basically use this interface. The antenna interface of SMA should be SMA, and SMA and RP-SMA are different. There are many types of SMA. One difference in polarity is called "SMA" and the other is called "RP-SMA". The difference between them is: the standard SMA is: "external thread + hole", "internal thread + needle" ", RP-SMA is: "external thread + needle", "internal thread + hole".

SMA antenna interface
The full name of the antenna interface of SMA should be the SMA inverse male connector, which is the antenna connector. The equipment is the most popular. APs with more than 70[%], wireless routers, and wireless network cards with more than 90[%] PCI interfaces all use this interface. This interface is moderate in size, and many handheld walkie-talkies and other devices are of this type. , But the needle and tube inside are opposite to the wireless device.
SMA connector type
The new generation of meters are equipped with SMA connectors or corresponding SMA adapters.

The quality of SMA connectors is also different. From the perspective of the impact on signal quality, a good SMA connector provides a good standing wave ratio, which has low signal reflection and can effectively transmit signals.

There are many types of SMA connectors. From the connection of the interface, there are male and female (or male or female). In terms of connection, some can be directly inserted on the side of the PCB. If it is inconvenient to insert on the side, it can be inserted on the top of the PCB. The middle is the signal, and the surrounding four pins are ground.

There are also screws fixed, mainly used for the side wall connection of the radio frequency circuit with a shielding box. There are four screws and two.