How to choose the best rf test cable(3)?

As a result, low-loss coaxial cables are a suitable choice to meet the above requirements, however, there are also shortcomings. It is usually not suitable for low-loss products to use finished connectors. You can only choose connectors specially designed for this type of cable. In this case, the production cycle will be prolonged and the cost will also increase. Low-loss center conductors may be more susceptible to being wet, contaminated with flux and cleaning agents, and will not peel off as easily as a solid center pin. These problems can complicate installation and increase costs.

This more flexible center structure makes it difficult to achieve high performance at higher frequencies. For example, if the corrugated center conductor on the braid is used too tightly, it will cause higher return loss. If the center conductor is very soft, the braided parts will move closer to each other, resulting in unstable radio frequency performance, especially in parameters such as phase or electrical length. And the center conductor will deviate from the center position, changing the impedance. Finally, low-loss cables are more susceptible to damage due to external physical pressure or other bending forces. The higher the Vp value, the more likely these problems are to worsen. It seems that low-loss coaxial cables have too many issues to consider, but in fact some issues are often overlooked.

Obviously, low-loss coaxialcables may need to meet or at least reach the target loss value, while at the same time they must meet the minimum bend radius/flexibility requirements. In order to achieve the customer's price and delivery goals, the softer PTFE medium can better meet the requirements of flexibility and bending life, and is closer to the bending radius requirements, but the loss value can reach 0.18db. LMR is a double-layer shielded cable product, while SFT is a highly shielded three-layer cable. Each uses a different center structure. It can be seen that it is not as simple as what customers expect to meet all requirements in a product.

Get the best performance and maximum value from the rf microwave test cable. Other properties of the test cable also make it an excellent cable product. Let's try to choose the right size connector for this cable. One way is to compare the diameter of the center conductor of the cable with the diameter of the center pin of the connector. Components of similar size make it match well at the connector, thereby optimizing return loss.

Generally, the joint connection of the coaxial cable assembly is the easiest to break, so the tension mitigation system needs to provide a smooth transition from the hard joint connection position to the cable. If the tension mitigation system cannot fix the connecting part of the joint or function as a lever point, it will not work and the joint will fall off prematurely. If possible, choose a solder joint method for the braid and the center conductor to achieve the longest service life and best electrical stability.

Unless the test system or component needs to consider the intermodulation, generally speaking, SMA connectors must use high-quality stainless steel materials instead of copper materials to achieve a long life. The use of steel connectors can increase the number of plugs and unplugs, and reduce the penetration of metal particles into the connector to change the impedance of the connector. If possible, the SMA connector series should have a hard and thick outer conductor design to reduce squeezing in the absence of a suitable wrench.

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