Coaxial Connectors

Coaxial connectors are composed of an insulated, central conducting wire wrapped in another cylindrical conductor (the shield). The cable is usually wrapped in another insulating layer and an outer protective layer. Coaxial cables and coaxial connectors have the capacity to carry vast quantities of information. They are typically used in high-speed data and CATV applications. A coaxial connector can be male or female in gender; have copper, gold, nickel, or silver plating; and be straight or right-angled. 

There are many different types of coaxial connectors. Many products use lettered or numbered designations. Lettered connectors include BMA, BMMA, BNC, BNC, DVI, FME, MCX, MMCX, MHV, RCA, SC, SMA, SSMA SMB, SSMB, SMP, TNC, UHF, XLR and ZNA connectors. Numbered devices include 1.6 / 5.6, 7-16, and 1.0 / 2.3 connectors. There are several types of numbered, metric coaxial connectors: 1.85 mm, 2.4 mm, 2.92 mm, 3.5 mm, and 7 mm, for example. Type C, Type F, Type G, Type N, Triax, Twinax, mini-UHF, USB Type A and USB Type B connectors are also available. USB is an acronym for universal serial bus. 

Performance specifications for coaxial connectors include impedance, frequency range, voltage rating, contact resistance, insulation resistance, voltage standing wave ratio (VSWR) and operating temperature. In terms of impedance, the nominal resistance is usually 50 or 75 ohms. Frequency range is the range of frequencies over which coaxial connectors are designed to function. Voltage rating is the maximum operating voltage. Contact resistance is the measurement of electrical resistance of mated contacts when assembled in a connector under typical service use. Insulation resistance is the electric resistance between two conductors separated by an insulating material. Voltage standing wave ratio (VSWR) is a unitless ratio ranging from 1 to infinity, expressing the amount of reflected energy at the input of the device.  A value of one indicates that all the energy will pass through, while any other value indicates that a portion of the energy will be reflected.

Coaxial connectors differ in terms of termination. Some devices use screws, lugs, tabs, or cage clamps. Others require crimping or wire wrapping. Insulation displacement connectors (IDC) slice through the cable insulation to make a connection. Through-hole technology (THT) mounts components on a printed circuit board (PCB) by inserting component leads through holes in the board and then soldering. In PCB solder or solder pin termination, electrical connection is made by soldering wires or pins onto a printed circuit board (PCB). With solder cup termination, soldering the connector onto the mounting location terminates the electrical connection.