Selecting an RF Connector for your Wireless System
The explosive growth of “wireless” systems has led to a simultaneous expansion in the use of RF connectors and their associated cables. These assemblies are increasingly vital links between multiple circuit boards, between antennas and front ends, and between power amplifiers (PAs) and antennas. They are instrumental to the operation of such wireless devices and systems as cellular telephones, wireless data networks and advanced radar and electronic-warfare (EW) systems.
Connectors for RF systems have the simple yet critical task of transferring signals from one location to another, with little or no change to the signal (although in reality even with high quality RF cable between the antenna connector and the antenna engineers often factor in a 0.2 dB loss per coaxial connector in addition to the cable attenuation itself).
There are a variety of connectors that are used for RF applications. Among the parameters that determine the best type for a given application are frequency range, Impedance, physical size, power handling, and cost. Recently, long-established connector types, such as the venerable BNC and the SO-239/PL-259, are being supplanted by connectors tuned to the priority characteristics of the latest wireless mass-market designs: smaller, designed only for low power, and providing excellent performance at 1 GHz+. The older connectors are not obsolete: they still are used in test equipment, rack and chassis designs, and installed base/legacy products.
Connectors and parameters
An RF connector is a precision-machined mechanical design and corresponding assembly which is actually quite complex, even if its outward appearance is simple. Consistent performance requires properly calculated dimensions, tight tolerances, quality surface plating/finish, and proper choice of materials.
Connectors have two general physical configurations: one which mounts on the PC board, the other for the mating cable (of course, there are also cable-cable pairings). The board-mounted connector is usually female, while the cable connector is generally male, although there are exceptions: you can purchase female body connectors with male center pins, and male body connectors with female inner sleeve (called reverse polarity connectors); this is an on-going source of user confusion. Nearly all connectors come as male/female gender mating pairs; there are a few hermaphroditic RF-connector styles available, but these are fairly rare in practice.
For more detail: Selecting an RF Connector for your Wireless System
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