A coaxial cable is one of the most common cable types used for RF signals, antennas, GPS, wireless communication, video equipment, and electronic devices.
Unlike ordinary electrical wire, coaxial cable has a carefully controlled internal structure. This structure helps carry high-frequency signals while reducing interference and signal loss.
If you are selecting a cable for an antenna, communication module, automotive system, or RF device, understanding the basic structure, impedance, cable type, and connector options can help you choose the right solution.
In this guide, we explain what a coaxial cable is, how it works, common coaxial cable types, the difference between 50 ohm and 75 ohm cable, and what to consider when sourcing a custom cable assembly.
What Is a Coaxial Cable?
A coaxial cable, also called a coax cable, is an electrical cable designed to transmit high-frequency signals.
The term "coaxial" comes from its construction. The inner conductor and surrounding outer conductor share the same central axis.
A typical coaxial cable contains four main parts:
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Center conductor
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Dielectric insulation
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Metallic shielding
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Outer jacket
This construction helps protect the transmitted signal from electromagnetic interference while maintaining controlled electrical characteristics.
Because of these properties, coaxial cables are widely used in RF, wireless communication, antenna, GPS, automotive, video, and test equipment.
For applications that require connectors on both ends, the cable is normally manufactured as an RF cable assembly.
What Is Inside a Coaxial Cable?
Although coaxial cables come in many sizes and constructions, most use the same basic layered design.
Center Conductor
The center conductor carries the electrical signal.
Depending on the cable, manufacturers may use solid or stranded conductors made from materials such as copper, tinned copper, or silver-plated copper.
Solid conductors can provide stable electrical performance, while stranded conductors generally offer better flexibility.
Dielectric Insulation
The dielectric layer surrounds the center conductor.
Its job is to keep the conductor centered and separated from the shield.
The material and dimensions of this layer directly influence the characteristic impedance and signal performance of the cable.
Common dielectric materials include polyethylene and fluoropolymer materials.
Shielding
The conductive shield surrounds the dielectric.
It provides the return path for the signal and helps reduce electromagnetic interference.
Depending on the required shielding performance, the construction may include braided shielding, foil shielding, or multiple shielding layers.
Outer Jacket
The jacket protects the cable against mechanical and environmental damage.
The correct jacket material depends on the application. Some installations require greater resistance to heat, abrasion, oil, chemicals, moisture, or repeated movement.
If you want to learn more about cable insulation and jacket materials, see our guide to wire insulation types.
How Does a Coaxial Cable Work?
A coaxial cable carries the signal through its center conductor while the surrounding shield acts as the outer conductor.
The spacing between these two conductors creates a controlled transmission path.
This is why cable geometry is important.
If the cable is crushed, bent too sharply, or terminated incorrectly, its internal geometry can change. At higher frequencies, this may affect impedance and increase signal reflections or insertion loss.
For this reason, an RF cable should not be treated as only a piece of wire with connectors attached.
The cable, connectors, cable length, termination method, and system impedance all contribute to the performance of the complete assembly.
Common Types of Coaxial Cable
There are many coaxial cable types available.
For compact RF and electronic applications, RG-series cables are still widely used.
| Cable Type |
Typical Impedance |
Main Characteristics |
Common Uses |
| RG174 |
50Ω |
Small, lightweight and flexible |
GPS, Wi-Fi, antennas, internal RF |
| RG178 |
50Ω |
Very compact, suitable for small devices |
RF modules, electronics |
| RG316 |
50Ω |
Flexible with good temperature capability |
Antennas, RF equipment, test devices |
| RG58 |
50Ω |
Larger and more robust |
Radio, antennas, general RF |
| RG59 |
75Ω |
Common video cable |
CCTV and video |
| RG6 |
75Ω |
Lower loss over longer distances |
CATV, satellite and broadband |
The best coaxial cable is not always the largest cable.
For example, RG174 may be suitable when installation space is limited, while a larger cable may provide lower attenuation for a longer RF connection.
You should therefore consider both mechanical and electrical requirements.
Our RF cable assemblies include different cable and connector combinations for antenna, wireless, automotive, and electronic applications.
50 Ohm vs 75 Ohm Coaxial Cable
One of the most important specifications of coaxial cable is characteristic impedance.
The most common values are 50 ohms and 75 ohms.
Industry references describe 50Ω as widely used for RF transmission applications, while 75Ω is frequently used for video and broadcast signal transmission.
50 Ohm Coaxial Cable
50-ohm coaxial cable is commonly used for:
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RF antennas
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Wi-Fi
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GPS
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Cellular communication
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Radio systems
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Wireless modules
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RF test equipment
Many SMA, UFL/IPEX, MMCX, MCX, N-Type, and automotive RF applications use 50-ohm transmission paths.
75 Ohm Coaxial Cable
75-ohm cable is commonly used for:
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CCTV
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Video equipment
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Television
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CATV
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Satellite systems
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Broadcast applications
The most important rule is to match the impedance of the cable to the rest of your system.
A 50-ohm device should normally use a 50-ohm cable and compatible connectors.
Impedance mismatch can cause signal reflection and reduce RF performance.
Where Are Coaxial Cables Used?
Coaxial cables appear in a wide range of products.
Antennas and Wireless Equipment
One of the most common applications is connecting an RF module to an antenna.
This can include:
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Wi-Fi equipment
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GPS modules
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Cellular devices
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IoT systems
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Radio equipment
A typical design might use a small UFL connector on the PCB and an SMA connector on the enclosure.
A custom cable assembly connects the two interfaces.
Automotive Electronics
Modern vehicles contain many RF communication systems.
Coaxial cables can be used for GPS, radio, cellular communication, infotainment, telematics, and vehicle antennas.
FAKRA connectors are commonly used in these applications because their coded housings help simplify connector identification.
For example, custom assemblies can combine FAKRA and SMA connectors with RG174 coaxial cable.
Electronic and Industrial Equipment
Coaxial cable assemblies are also used in:
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RF instruments
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Measurement equipment
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Industrial electronics
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Communication equipment
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Antenna systems
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Test fixtures
The required cable type depends on frequency, length, shielding, connector interface, and environmental conditions.
Common Coaxial Connector Types
Choosing the correct connector is just as important as selecting the cable.
Common RF coaxial connectors include:
SMA
Frequently used for antennas, GPS, Wi-Fi, communication equipment, and RF instruments.
UFL / IPEX
Very small connectors commonly used on PCBs and wireless modules.
FAKRA
Common in automotive RF, GPS, antenna, and infotainment systems.
BNC
Often used for test equipment, CCTV, RF instruments, and communication systems.
MCX and MMCX
Compact connectors suitable for GPS, wireless devices, and embedded electronics.
N-Type
A larger and more robust RF connector commonly used for external antennas and communication equipment.
Our RF cable assembly range includes various connector and cable combinations for custom projects.
How Do You Choose the Right Coaxial Cable?
There is no single coaxial cable that is suitable for every application.
Before selecting one, consider these key factors.
Operating Frequency
Higher frequencies make cable loss and impedance control more important.
Always identify your operating frequency before selecting the cable.
Cable Length
Signal attenuation increases as cable length increases.
A miniature coax may work well for a short connection inside a device but may not be the best solution for a long antenna cable.
Impedance
Confirm whether your system requires 50Ω or 75Ω.
The cable, connectors, antenna, and equipment should use compatible impedance wherever possible.
Connector Type
The connector needs to match both the system interface and the physical cable construction.
For example, SMA connectors designed for small RG174 cable use different termination dimensions from connectors designed for larger RF cables.
Flexibility and Installation Space
Compact electronics often require flexible cables that can pass around PCBs, housings, and other components.
However, very tight bends can deform the cable and affect its performance.
Working Environment
Consider temperature, vibration, moisture, chemicals, outdoor exposure, and repeated movement.
These conditions may affect the cable jacket, connector plating, strain relief, and sealing requirements.
Why Does Cable Assembly Quality Matter?
A high-quality cable can still perform poorly if the connector is terminated incorrectly.
During coaxial cable assembly production, important factors include:
Poor termination can create impedance discontinuities or reduce mechanical reliability.
This is why custom RF assemblies should be manufactured and tested as complete assemblies rather than evaluated only by cable type.
How Are RF Cable Assemblies Tested?
Testing requirements depend on the application.
Basic assemblies may require continuity, short-circuit, dimensional, and visual inspection.
Higher-frequency RF applications may also require tests such as:
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Insertion loss
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VSWR
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Return loss
IEC 60966-1 establishes general requirements and test methods covering electrical, mechanical, and environmental properties of RF coaxial cable assemblies.
When requesting a custom cable, it is better to specify the actual required test rather than simply asking whether the cable is "tested."
What Information Should You Provide for a Custom Coaxial Cable?
Providing complete specifications can make quotation and production much faster.
You should normally provide:
For example:
RG316, 50Ω, SMA female bulkhead to UFL, 300 mm, GPS application, 1,000 pcs.
This gives the manufacturer much more useful information than simply asking for an "SMA antenna cable."
Frequently Asked Questions
What is a coaxial cable used for?
Coaxial cable is commonly used to transmit RF, antenna, GPS, wireless, video, and communication signals while reducing external electromagnetic interference.
What is the difference between coaxial cable and normal wire?
A normal wire mainly carries electrical current or low-frequency signals. A coaxial cable uses a center conductor and surrounding shield with controlled geometry to maintain characteristic impedance and support high-frequency signal transmission.
Is coaxial cable 50 ohm or 75 ohm?
Both are common. 50Ω cable is widely used for RF and wireless applications, while 75Ω cable is commonly used for video, broadcast, and CATV applications.
Which coaxial cable is best for an antenna?
It depends on frequency, cable length, signal loss, installation space, connector type, and operating environment. Small cables such as RG174 can work well for short antenna connections, while longer connections may require a lower-loss cable.
Can coaxial cable assemblies be customized?
Yes. Cable type, connector combination, length, orientation, heat shrink, sealing, and other features can be customized according to your application and drawing.
Custom Coaxial Cable Assemblies for Your Project
Choosing the right coaxial cable means considering more than the cable number.
Frequency, impedance, cable length, signal loss, connector compatibility, installation space, and operating environment should all be evaluated together.
We manufacture custom RF cable assemblies, micro coaxial cables, and other custom cable assemblies for electronic, communication, automotive, antenna, and industrial applications.
If you need an SMA to UFL cable, FAKRA cable assembly, BNC cable, MMCX assembly, RG174 cable, RG316 cable, or another custom RF configuration, send us your drawing, cable specifications, connector requirements, and order quantity.
Contact us for a custom coaxial cable assembly quotation.
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