Do I need SMA or RP-SMA

The particular application you're using will determine whether you require SMA or RP-SMA connections.

Microwave applications frequently employ SMA connectors (SubMiniature version A), a type of RF connector. They generally operate at frequencies up to 18 GHz and include a distinctive screw-type connection mechanism. Devices like wireless routers, cell phones, and other items that employ radio frequency technology frequently use SMA connections. An alternative to SMA connections are RP-SMA connectors (Reverse Polarity SMA).

RP is abbreviation of "Reverse Polarity", which stands for RP-SMA connector (sometimes also referred to as reverse SMA or for short "R-SMA"). It is intended to stop unauthorized to connect to external antenna.

Be careful since connecting an RP-SMA plug to a normal SMA jack can ruin the connector. as a result of the gender transition. The RP-SMA plug is a screw sleeve with internal threads, but instead of a pin, it contains a socket for an inner conductor. Although the RP-SMA jack socket has a central pin, it still has external threads.