Custom RF Cable Assemblies: The Ultimate Guide To RF Cable Assembly

To accommodate special applications, there’s a need for specially designed custom RF cable assemblies. However, the question still remains: what factors should you consider when designing a custom RF cable?

What Are Custom RF Cable Assemblies?

An alternating current generates Radio Frequency (RF) waves while moving through a conductive material, which can transmit through coaxial cables.

RF cable assemblies are coaxial cables with RF coax connectors mechanically attached. It functions as a transmission line for RF signals moving from a given point in a system to another.

Vendors offer coaxial assemblies preassembled for a certain use. If performance parameters, the length, and the coaxial connector type are known for that application, an RF cable assembly may be the best choice.

However, applications such as avionics, military, space, government, naval, and industrial installations have specific requirements and regulations for RF coaxial cable assembly. A custom RF coax cable assembly is likely the best choice for these specifics.

Custom RF Cable Assemblies Considerations

When designing an RF cable assembly, there are several variables to consider.

Coaxial Cable Types

Coaxial refers to the outer shielding and inner conductor sharing a geometric axis. Applications such as scientific experimentation, test and measurement, high-performance radar, and satellites require specifically designed RF coaxial cables.

Hardline

Made using aluminum, steel, copper, or silver for the center conductor and shielding.

Therefore, the cables are thick, and you can use them for high-strength applications like military signals or broadcasting radio between an antenna (aerial receiver) and ground-level receiver.

Furthermore, hardline cables might have a dielectric buffer like pressurized nitrogen or polyethylene foam to prevent moisture contamination or arching.

Shielding materials vary from corrugated to rigid tubing.

RG-6 Coaxial Cable

This cable is made with a bare solid copper or copper-clad steel center. It’s the most common coaxial cable since its main use is to relay cable TV signals.

Furthermore, it is available in 4 different variations, including;

Plenum – surrounded by a teflon-based outer jacket to adhere to the ventilation duct fire codes.
Plain – for standard outdoor wiring or indoor house wiring.
Messenger – having steel wiring to bear the tension from the aerial drop of the utility rope.
Flooded – it has an additional water-blocking gel for underground conduits.

RG-11 Coaxial Cable

It is an inflexible thick cable you can use to reduce signal loss in long runs, ideal for underground and outdoor runs.

RG-59 Coaxial Cable

This cable functions similarly to the RG-6 cable but has a slimmer center conductor. However, the difference makes RG-59 cables ideal for indoor low-frequency transmission and short runs.

Triaxial Cable

Sharing a similar structure with coaxial cables, such cables have an additional layer of insulation and a second conducting sheath.

Therefore, they are more expensive but offer better bandwidth and lower interference.

Usually, you can use them for TV productions exposed to electromagnetic forces.

Twin Axial Cable

Commonly known as Twinax, such cables share a similar structure to coaxial cables.

However, instead of having one central conductor, they have two.

Therefore, people mainly use them for short-range high-speed signaling applications like network hardware with SFP+ interfaces.

Semi-Rigid Coaxial Cable

With a shield made of a solid conductor instead of stranded wires and PTFE-supported dielectric, semi-rigid cables offer better dielectric properties to enable high performance at high frequencies.

However, semi-rigid cables are limited in frequency transmission and size.

Rigid Coaxial Cable

Rigid cables have 2 copper tubes and a PTFE dielectric buffer supported on each end and several intervals.

Compared to semi-rigid cables, rigid cables are bigger and offer power capacities capable of operating FM and TV frequencies with multi-channel transmission.

Furthermore, there are several important factors to consider when making a decision on an RF coaxial cable for an application, including:

the frequency range;

the transmission power levels;

the electromagnetic and RF environment;

the length;

the complex of the routing;

the budget;

and regulatory requirements.

Connector Types

RF connectors are specially designed to function with signal transmission products such as coaxial cables, radios, and antennas. They help maintain the cable’s shielding and connect devices to cables.

Type-N Connectors

Type-N connectors are threaded medium-sized weatherproof for durable applications capable of managing frequencies of 11 GHz.

You can mainly use this connector in low-frequency microwave systems that require low costs, robustness, and stability.

UHF Connectors

Ultra high-frequency connectors are threaded RF connectors that transmit signals at frequencies of 100 MHz.

Unlike type-N connectors, UHF connectors do not have non-constant surge impedance and are waterproof.

Also, they are often applied in marine VHF radio, amateur radio, and citizen band radio applications.

BNC Connectors

BNC connectors are small quick disconnect/connect RF connectors mainly used for low-frequency connectors.

However, they were initially employed in the military field and significantly gained acceptance in RF applications of up to 2 GHZ and composite video and commercially utilized video devices.

BNC connectors are convenient and easy to use, delivering high-performance levels.

Additionally, you can use them on power meters to function generators and test equipment such as audio generators.

Furthermore, you can use these connectors in applications requiring screened or coaxial cables, especially for RF applications.

Caption: BNC Connectors

TNC Connectors

This is a threaded version of the BNC connector. However, they are ideal for microwave frequencies because they have better performance than BNC connectors.

Therefore, they are mainly employed in wire and radio applications.

SMA Connectors

SMA connectors are semi-precision coax RF connectors capable of operating at 18 GHz. However, some variants can operate at up to 26.5 GHz.

You can use SMA connectors in RF isolators, radio astronomy at over 5 GHz, WiFi antenna systems, mobile telephone antennas, and RF power amplifiers.

Caption: SMA Connectors

On the contrary, not all cables are built for certain connection types, so when deciding on an RF connector, you should consider:

Cable size;

Cable resistance (50 Ohms or 75 Ohms; it’s vital to equal impedance in the same system. Also, to reduce system complexity and cost, try not to rely on an impedance matching device. );

Cable shielding type;

The Cable Center conductor type;

Cable additional layers;

Cable installation position (Right angle RF adapters and connectors are ideal for the RF cable placed perpendicularly to the mated radio frequency connector. Such connectors are mostly available in 90⁰ and 45⁰ angle options.);

the frequency range;

the transmission power levels;

the electromagnetic and RF environment;

Types of metals used on both cables and connectors;

Attached ways including crimping, soldering, tool-less press-fit, and so on;

The matching system, device, or other interconnect the coaxial cable will be mated with. (With bigger RF connectors like type-N,

SMA and TNC, the female and male connectors are threaded to secure them together. On the other hand, smaller RF connectors like MMXC or UFL are mated using detents or locking rings.)

Optimized connectors for Low PIM or low-loss applications

Custom RF Cable Assembly Solutions at Cloom

From conventional configurations to multiport, bundled, and custom solutions, Cloom has the expertise to ensure you get the best RF configuration.

Cloom, an ISO-certified manufacturer of custom cable assembly and wiring harnesses, automates (crimping and stripping) whenever possible.

Therefore, it is impossible for us to quickly process custom RF cables in large quantities.

Over 250,000 Custom RF Configurations Available

You can pick from more than 1000 RF coaxial connectors.

Pick your ideal custom lengths (standard or metric).
You can choose from over 100 cable types.

Value Added Services Include:

Custom coaxial cable assembly, harnessing, and labeling
Custom cold shrink/heat shrink/booting or no weatherproofing
Custom clocking of right-angle coax connectors
Several armor cable designs
Custom pigtail assembly

Full-Service Testing Including:

PIM testing to -160 dBc (-117 dBm)
RF testing to 65 GHz
Hi-Pot testing to 6,000 volts AC and 5,000 volts DC
Phase matching +/-20 GHz

Conclusion

There, you have all you need to know about custom RF cable assemblies. Now, you can make a more informed decision regarding the best RF cable for your application. For all your custom RF cable needs, feel free to contact Cloom Tech.