RF signal has its own characteristics, so the transmission of signal requires a special medium, the corresponding connector is also very special, here is the main description of the common rf coaxial connector, in accordance with gb11316-89, IEC169 standards, mil-c-31012 and other standards.

    First. common coaxial connector and main performance table:

    In addition to the above connectors, there are MINI BNC, SL16, C3, CC4 (1.0/2.3), SMZ (bt-43), MIM and other connectors, but mainly some of the company's models.

    Second. Selection of common coaxial connectors

    BNC is bayonet type for RF connections less than 4GHz and is widely used for instrument and computer interconnections.

    TNC is thread connection, similar to BNC in size, operating frequency up to 11GHz, thread for vibration environment.

    SMA is the most widely used, impedance of 50 and 75 ohms, 50 ohms, soft cable use frequency is lower than 12.4Ghz, semi-rigid cable up to 26.5 Ghz.

    SMB connector is smaller than SMA in size and for fast connection inserts self-locking structure, commonly used for digital communication, is L9 replacement, 50 ohm to 4GHz, 75 ohm to 2GHz.

    SMC is a threaded joint and other similar SMBS with a wider frequency range and is commonly used in military or high vibration environments.

    N Type connector is screw, air insulation material, low cost, frequency up to 11GHz, often used in test equipment, there are 50 and 75 ohms two.

    For dense connections, the MCX and MMCX connectors are small.

    BMA for blind plug connections for low power microwave systems up to 18 GHz.

    Each connector comes with military and commercial standards. The military standard is made by mil-c-39012, copper parts, PTFE insulation, inside and outside gold-plated, most reliable performance, but at a higher cost.

    Commercial standard designs use inexpensive materials such as brass castings, polypropylene insulation, and silver coatings, which are less reliable.

    The connector materials are brass, beryllium copper and stainless steel, and the center conductor is usually gold-plated to ensure low resistance and corrosion resistance.Military standards require gold plating on SMA and SMB, and silver plating on N, TNC and BNC, because silver is easy to oxidize and users prefer nickel.

    Insulation material has polytetrafluoroethylene, polypropylene and toughened polystyrene, polytetrafluoroethylene insulation performance is the best, but the cost is higher.