[Sponsored] As electronic systems continue to evolve toward higher frequencies and greater complexity, ensuring the performance of every component in the signal chain becomes vital. In RF and microwave systems, connectors and cables play a decisive role in overall system performance. For advanced systems, whether in aerospace, instrumentation, or high-speed computing, signal integrity (SI) is paramount. In these circumstances, precision RF connectors are essential.
With frequencies approaching 110 GHz, a mismatch in impedance, an increase in insertion loss, or minute phase distortion can be the difference between success and failure. This is why RF connectors designed for these frequencies are manufactured to such exacting tolerances. The precision is critical to achieving optimal performance. They ensure that signals are transmitted cleanly and consistently, without the distortions and degradations that can plague commercial-grade connectors.
However, connectors do not work in isolation. They are just one part of a larger, interdependent system that includes the cable and the broader interconnect architecture. Achieving peak performance requires an integrated approach in which every component is engineered to work as a whole. The result is a system with low signal loss, enhanced phase stability, and better electromagnetic shielding along the entire transmission path.
The design of any high-performance coaxial cable relies on controlling the critical relationship between the conductor and shield. The shield represents a compromise between delivering the best RF performance with the flexibility that a cable requires. Most manufacturers achieve this using a combination of a conductive foil or tape inner layer, paired with a woven braid that covers the foil.
Samtec’s NITROWAVE is a range of high-performance RF cables designed for microwave and millimetre wave (mmWave) applications. In common with many coaxial cables, NITROWAVE uses silver-plated copper as the material for both the foil and braid, with an FEP (Fluorinated ethylene propylene) jacket in Samtec’s signature orange colour to provide protection in some of the toughest conditions. Designed for demanding applications in the aerospace and defence markets, along with instrumentation and computing industries, the FEP jacket delivers a high working temperature and resistance to abrasion.
However, an unseen feature of NITROWAVE is the dynamic performance layer (DPL). The DPL is a key component in the cable’s construction, made from a layer of PTFE between the foil and braid shields. Although thin, the DPL plays a critical role in NITROWAVE’s mechanical and electrical performance. Its primary intention is to eliminate friction between the two elements of the shield, allowing the braid to move freely over the foil without damaging it. The DPL also improves overall reliability. Its PTFE layer wraps around the helical foil shield, improving the cable’s strength when flexing. It provides an interface between the delicate foil and the woven braid that surrounds it, reducing the risk of conductive oxidation. The result is a cable with a higher flex cycle life and improved durability.
Enhancing RF performance
The advantages of the DPL are not limited to improved mechanical performance. These improved physical properties also enhance electrical performance. DPL provides better phase stability. Phase is the name given to the position of a wave at a specific point in time within its cycle and is important when considering how RF signals travel along cables. A phase shift is therefore a change in the position of the wave, usually caused by external forces such as bending of the cable or changes in its temperature. Greater phase stability results in more consistent RF signals, even when the cable itself is flexing.
The DPL layer also helps to reduce capacitive coupling. This is a side effect created by the two separate shield layers. If in close contact, the layers act as the plates in a capacitor. Even the tiny amounts of electrical charge that can build up between the layers have the potential to create unwanted noise, which will have an impact on signal integrity. A thin PTFE layer such as that used in NITROWAVE is sufficient to minimise this coupling and improve overall SI performance.
NITROWAVE for all applications
The performance of NITROWAVE may suggest that it is suitable only for the most demanding applications. Some customers may decide against using a cable intended for 110 GHz performance in their design. However, NITROWAVE is not one product. Instead, it is a family of cables, each optimised for different frequencies ranging from 18 GHz up to a maximum of 110 GHz. These frequencies were selected with care following extensive studies of customer requirements, with each cable designed to minimise insertion loss across its operating frequency range.
Conclusion
NITROWAVE cables are designed to deliver superior performance in combination with Samtec’s range of Precision RF connectors. Engineered to the same tight tolerances, these connectors ensure optimal signal integrity and mechanical reliability across the entire signal path.
Whether operating at mmWave frequencies or in harsh environmental conditions, the combination of NITROWAVE cables and Samtec Precision RF connectors delivers a fully integrated, high-performance interconnect solution. Visit the Samtec website [www.samtec.com] for an in-depth view of the features of NITROWAVE. You can also download the guide to precision RF design [suddendocs.samtec.com/literature/samtec_precision_rf_design_guide.pdf].
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