Inside of enclosures and cases for PCB boards, there is very limited space for the RP-SMA antenna connector and coaxial cable. In such cases the RP-SMA right angle connectors, cables and adapters fit the bill.
Typically mini-PCI cards are connected to an antenna using a cable with U.FL or MMCX on one end and RP-SMA female on the other end. Data Alliance is a top manufacturer of such cable assemblies.
Coaxial cables leak signal (signal loss), so it is very important to keep the length of cable to a minimum. Also, about 1/2 dB is lost in each connection made, so it’s important to reduce the number of connections between cables and RF adapters as much as possible: Try to use just one cable to make the entire length to the antenna, rather than connecting cables with adapters, or using a second cable as an extension cable.
Coaxial cables for antennas are assembled by soldering the center wire inside the coaxial cable onto an antenna connector (also called RF connector), on the side of the cable that attaches to an antenna: Typically, indoor antennas have an RP-SMA connector: Dipole antennas have a male connector and panel antennas have a female RP-SMA connector. The other end of the coax wire will be soldered either to a Printed Circuit Board (PCB), or to an MMCX or U.FL connector that will attach to the jack on the miniPCI card.