If you have performance parameters for a set of cable assemblies, you can compare cables from different vendors to determine the best value in the coaxial cable assembly. However, the needs of each application often determine the specific requirements of the cable assembly or cable assembly group. Even assuming a common characteristic impedance, such as 50Ω, the requirements for electrical and mechanical cables can vary greatly from system to system, such as the weight of the cable in the onboard system and the importance of the ground system, and the connectors that need to be mated with it. Types of. System, operating frequency range, operating temperature range and power handling capabilities.
A good starting point for specifying a cable assembly for a given application might be to determine the connector. The connector not only limits the performance of the cable assembly, such as frequency range and power handling capabilities, but also determines the range of available coaxial cable diameters. For example, a larger diameter cable will support the termination of the N-type connector, while a smaller diameter cable will better match a smaller connector, such as an SMA connector. N-type connectors provide excellent electrical performance at 11 GHz, while SMA typically has the same attenuation and return loss performance at 18 GHz.
In some applications, particularly in commercial communication systems that use digital modulation, intermodulation distortion (IMD) performance of coaxial cable assemblies can be a key parameter. Comparisons are usually made based on the passive intermodulation (PIM) of the cable. In terms of reduced bit error rate (BER) performance, excessive PIM is typically evident for communication standards. The PIM levels of different coaxial cable assemblies can be compared relatively, but there is currently no PIM as the industry standard for absolute reference. It should be noted that the acceptable PIM level of the cable assembly is somewhat arbitrary and the measurements may vary depending on the test method and environment.
Other cable component parameters that need to be considered when meeting application requirements are applications for indoor, outdoor, air, space or test laboratories. A coaxial cable assembly with a particular material may be required to use the location. For example, cables for outdoor use typically require an outer jacket of some form of plastic or thermoplastic for environmental protection. Cable jackets for outdoor applications may require oxidation or ultraviolet (UV) light. Moreover, some locations may require a cable assembly with a refractory outer jacket.