May 4, 2023

What is CELLFLEX®?

It may be one of the longest standing solutions in the RFS portfolio, however CELLFLEX®, which has continually evolved over the decades, is still the go-to for a huge range of applications. In this week’s blog, Andreas Bergmeister, Global Product Manager, Transmission Lines at RFS talks about CELLFLEX; how it has changed and how it is continuing to meet the needs of our customers.

Andreas Bergmeister, Global Product Manager Transmission Lines

Can you give us an overview of RFS's CELLFLEX portfolio?

The CELLFLEX family is a complete portfolio of low loss and high flexibility foam dielectric RF broadband cables in all sizes from ¼” to 8”. Along with long length cable, CELLFLEX feeder cables are the basis for our comprehensive factory fit jumper portfolio which have the advantages of premium VSWR and IM levels.  

Each cable has a copper or aluminum corrugated outer conductor and has been designed by RFS to deliver premium performance with a solution that works for decades without degradation. To meet the changing needs of the industry, we have extended the broadband standards of the cable portfolio to include 5G, CBRS, LAA as well ensuring our solutions are ready to meet future frequency requirements.

Beyond its high performance, CELLFLEX is also designed to meet or exceed the requirements of the regulations and standards our customers must conform to. All cables are available with a standard PE outdoor rated jacket or special indoor jacket composition that meets the highest fire standard including e.g. CPR and IEC. 
How long has RFS offered this type of solution and how has it changed over the years?

RFS invented this type of coaxial cable 1961 – the first of its kind on the market. However more than six decades later, corrugated feeder cables are still the industry standard for the whole wireless industry.

As the mobile communications industry standards have evolved, the requirements on maximum frequency have continuously changed. For example, during the 2G/3G (UMTS/CDMA/WCDMA/AWS) era, 2 ¼” size CELLFLEX cable was very popular as it minimized cable losses up to an operating frequency of 2200 MHz. However, as we moved to 4G, the existing cables were not able to support 4G (LTE) standards which utilized the 2500 – 2700 MHz band. 

The limitation in maximum operational frequency of 2 ¼” cable pushed the industry towards favoring smaller cable diameters. Also, as the typical deployment scenarios moved away from needing to address coverage constraints towards overcoming capacity challenges, different CELLFLEX cables have more appropriate to deliver the requirements of customers. 

In addition to moving requirement, the landscape has also changed. Radio Remote Heads bring RF energy much closer to the antenna where it is needed, and so a different cable configuration is needed to accommodate this set up and unlock its advantages. 
In short, as things change in the industry, so does our portfolio. 

Can you give an example of a deployment using CELLFLEX?

This type of cable is an essential part of the infrastructure needed to support all mobile calls both using MNO networks and for mission critical communications. As a result, the number of deployments using CELLFLEX around the world is vast, but we can look at a few examples. 
Custom CELLFLEX cables were manufactured to meet urgent requirements for temporary base stations following flooding in Germany. CELLFLEX is used alongside our RADIAFLEX cables across underground rail systems including in Japan and Paris to deliver a complete in tunnel communications infrastructure. They are used to ensure optimum performance at Macro Sites. They form part of the DAS and DRS solutions that we offer to deliver in-building connectivity. Put simply, it is a solution that is flexible both in form and application with optimum performance at the center of what it offers. 

Beyond CELLFLEX itself, are there any other products from RFS that help make the most of the cable solution?

To ensure premium RF performance we have a dedicated range of connectors designed to maintain the performance of our CELLFLEX cables. Our OMNI FIT connectors exceed the industry standard Voltage Standing Wave Ratio (VSWR) and PIM performance and are available for all CELLFLEX cables and for all interface combinations requested by the market.

Additionally as part of the CELLFLEX family we have a full range of state-of-the-art accessories, including grounding kits, hangers and the corresponding installation tools that ensure customers reap the full benefits of our premium cable solutions.

Is the CELLFLEX portfolio continuing to evolve and how is this benefiting customers?

The communication industry is never static, and standards will continue to evolve to serve changing needs. New spectrums and frequencies will be allocated and will need to be transported via cables. New interfaces like Next Gen cluster connector solutions or Next Gen MultiCoax cables are in development so we and our customers are prepared for the future. The cable portfolio will continue to be updated according to those needs and incorporate additional products, such as FLEXWELL waveguides, to work with high frequencies. 

Beyond addressing the technical needs of customers, we are also continually looking at all the ways to reduce Total Cost of Ownership. One example is through the packaging of our cable solutions. The flexibility of CELLFLEX allows it to be wound onto drums with a narrow diameter. This detail allows for the most compact and efficient shipping, lowering the overall logistics cost which is passed on to customers as one of several ways we work to reduce CAPEX and in turn TCO. 

Throughout our history, RFS has constantly developed the solutions that meet the ever-changing needs of the industry, we are continuing to update and innovate to maintain this and best meet the needs of our customers.

About the author

Andreas Bergmeister

Global Product Manager Transmission Lines