Types of coaxial cable connectors and how to choose them

Coaxial cable connectors are used in a variety of situations, but choosing the right connector is important.

In this article, we will introduce the main types of coaxial cable connectors, explain their features and applications, and what to consider when choosing one.

Basic knowledge of coaxial cable connectors

Coaxial cable connectors are essential components for connecting communication and video equipment. Knowing how to choose and handle them correctly can help prevent connection problems and signal loss.

Here we will explain the basics about coaxial cables and connectors.

What is Coaxial Cable?

Coaxial cables are special cables designed to efficiently transmit high-frequency signals. They consist of a central conductor, an insulator, an outer conductor (shield), and an outer coating layer. This structure prevents external electromagnetic interference and minimizes signal loss.

Coaxial cables are used for a variety of purposes, including TV antenna connections, cable TV, Internet lines, and wireless communication devices. They are particularly good at transmitting high-frequency signals, making them useful for transmitting high-quality audio and video signals over long distances. Another major feature is that they are relatively flexible, making them suitable for use in complex wiring routes.

What is a coaxial connector?

Coaxial connectors are connection parts designed specifically for coaxial cables. Coaxial cables are primarily used in wireless communications, broadcasting, networks, electronic measuring instruments, etc., and there are many different types depending on the application.

Each cable requires a different coaxial connector, and there is a corresponding connector for each type of cable, so it is important to choose the right coaxial connector for the coaxial cable you are using.

When connecting, two different types of coaxial connectors are required for the source and destination. Also, the type of coaxial connector used differs depending on whether you are connecting cables to each other or connecting a cable to a device panel or printed circuit board. Depending on the product, the cable connection method may be soldered or crimped, providing even more options.

There are many types of coaxial connectors, and the right one is selected depending on the application, frequency band, and environmental conditions. Each connector is optimized for a specific frequency range and application, and is designed to be easily inserted and removed while maintaining signal quality. Choosing the right connector will help maintain signal quality and maximize the performance of your entire system.

Coaxial Connector Types

This section explains the following typical connector types and their features.

• BNC type
• N-type
• TNC type
• SMA type
• SMB type

We will introduce the shape, characteristics, and general range of use of each connector, so please use this as a reference when selecting a connector.

BNC type

BNC (Bayonet Neill-Concelman) style connectors are the most widely used coaxial connectors. These connectors feature a bayonet-style locking mechanism that allows for easy connection and disconnection. When connected, they rotate to lock in place, preventing them from coming loose due to vibration or shock.

BNC type connectors are compatible with a wide range of frequency bands, and in theory can be used up to 4 GHz. However, in practice they are mostly used in frequency bands below 1 GHz, and because of their reliability and ease of use, they are widely used in a variety of fields, including television broadcasting equipment, oscilloscopes, and network equipment.

They are also relatively inexpensive and easy to handle, making them a common connector found in general electronic devices and test equipment, but their performance in the high frequency range may be inferior to other dedicated connectors.

Connection Method	Bayonet lock system
Characteristic Impedance	50 ohms, 75 ohms
Frequency range	4GHz or less
Rated voltage	500V (effective value) or less

N-type

Type N connectors are durable connectors designed for high frequency applications. They use a threaded connection system that provides a secure connection and excellent electrical properties. They are typically used for frequency bands up to 10 GHz, but in some cases can be used even higher.

N-type connectors are widely used in devices that handle high-frequency signals, such as wireless communication devices, antennas, and measuring instruments. They are particularly suitable for use outdoors and in harsh environments, and have excellent weather resistance and durability. Although they are not suitable for small devices due to their relatively large size, they are characterized by stable electrical performance and high reliability.

Connection Method	Screw 5/8-24UNEF-2A, 2B
Characteristic Impedance	50 ohms, 75 ohms
Frequency range	10GHz or less
Rated voltage	500V (effective value) or less

TNC type

The TNC (Threaded Neill-Concelman) connector is a screw-in version of the BNC type. It was designed to combine the simplicity of the BNC type with the reliability of the N type. It is mainly used in frequency bands up to 4 GHz and can maintain a stable connection even in environments with a lot of vibration and shock.

TNC type connectors are widely used in fields that require high reliability, such as mobile communication devices, aviation equipment, and military equipment. They perform better in the high frequency range than BNC types, and are chosen when a more reliable connection is required. However, they take longer to connect and disconnect than BNC types, so care should be taken if frequent connection and disconnection is required.

Connection Method	Screw 7/16-28UNEF-2A, 2B
Characteristic Impedance	50Ω
Frequency range	4GHz or less
Rated voltage	500V (effective value) or less

SMA type

SMA (SubMiniature version A) type connectors are small, high-performance coaxial connectors. They can generally be used in frequency bands up to 18 GHz, making them suitable for high-frequency circuits and precision equipment. Some products can be used up to 25 GHz. They use a screw-in connection method, and are characterized by their small size but reliable connection.

SMA connectors are used in a wide range of applications, including wireless LAN antennas, mobile phones, satellite communication equipment, and test and measurement equipment. Their small size makes them suitable for use in equipment and circuit boards with limited space. However, because they are so small, they can be damaged if excessive force is applied, so care must be taken when handling them.

Connection Method	Screw 1/4-36UNS-2A, 2B
Characteristic Impedance	50Ω
Frequency range	18GHz or less
Rated voltage	335 to 500V (effective value)

SMB type

The SMB (SubMiniature version B) type connector is a coaxial connector that is even smaller than the SMA type. It is mainly used in frequency bands up to 4 GHz, and features a snap-on connection method that allows for quick connection and disconnection. Because it is small and lightweight, it is suitable for equipment with strict space and weight constraints.

SMB type connectors are widely used in fields where miniaturization is required, such as mobile devices, automotive electronics, and industrial equipment. Because it is a snap-on type, it can be quickly connected and disconnected, but it is weaker than other screw-type connectors when it comes to strong shocks and vibrations. It is necessary to select the appropriate connector depending on the usage environment and conditions.

Connection Method	Snap-on method
Characteristic Impedance	50Ω
Frequency range	4GHz or less
Rated voltage	500V (effective value) or less

Optimal Frequency for Coaxial Connectors

Coaxial connectors must be selected appropriately depending on the frequency band to be used. Each connector has a frequency range that it can handle, and exceeding this range can cause signal loss or degradation, so care must be taken. Generally, the smaller the connector, the higher the frequency it can handle. To select the appropriate connector, it is important to carefully check the specifications and usage environment.

As mentioned in the previous chapter, SMA and N-type connectors, which support high frequency bands, are particularly suited to applications that require high accuracy, such as wireless communication and radar. On the other hand, BNC and TNC types can provide stable connections in the low to medium frequency bands, so they are widely used in televisions and video equipment. However, it is important to remember that the appropriate frequency range will vary depending on the actual usage environment and the required performance.

How to connect a coaxial connector

The method of connecting coaxial connectors varies depending on the type of connector. By understanding and properly performing the correct connection method, it is possible to maintain signal quality and maximize the performance of the equipment. This section explains the most common connection methods.

For screw-in connectors (N-type, SMA-type, etc.), mate the male and female sides and connect them by firmly tightening the screw part. It is important to tighten with the appropriate torque, and be careful not to apply excessive force as it may cause damage.

Bayonet-type BNC connectors are locked by inserting the male into the female and rotating it approximately 90 degrees. This method allows for quick connection and disconnection, but you must check to make sure it is securely locked. Snap-on connectors such as SMB connectors can be connected by simply pushing them straight in. However, while they are easy to connect, they can easily come off if pulled carelessly, so care must be taken.

In either case, it is important to check the condition of the connectors before connecting them and clean them if necessary. Also, don't forget to ensure that the cables are properly routed so that they are not subjected to excessive strain.

How to Choose a Coaxial Connector

Choosing the right coaxial connector can greatly improve signal stability and connection reliability. Here are some points to keep in mind when choosing a connector:

• frequency band
• Impedance
• Environmental condition
• Size and weight
• Connection Frequency
• Electrical Performance
• cost
• Standards Conformity

Frequency band: Choose a connector that supports the frequency band you will be using. The higher the frequency, the higher the performance of the connector you need. When using high frequencies, connectors such as SMA type and N type are suitable.

Impedance: It is important to match the impedance of the cable and connector. Typically you will choose either 50Ω or 75Ω.

Environmental conditions: For outdoor use or where waterproofing is required, we recommend the durable N-type connector, while for lightweight and compact applications, small connectors such as SMB type are suitable.

Size and Weight: Select the appropriate size connector depending on the space and weight limitations of your equipment.

Frequency of connection: If you need to connect and disconnect frequently, a bayonet or snap-on connector is convenient.

Electrical Performance: Select a connector that meets the required electrical characteristics such as insertion loss, return loss, and power resistance.

Cost: You also need to consider the balance between price and performance. High-performance connectors generally cost more, but you should choose a product that offers the best cost performance for your application.

Compliance: It is also important to select connectors that comply with the equipment and industry standards being used.

Consider all these factors and choose the coaxial connector that best suits your needs.

Summary

Coaxial cable connectors are components that play an important role in transmitting high-frequency signals. There are various types of coaxial connectors, such as BNC type, N type, TNC type, SMA type, and SMB type, and it is important to select the most suitable one according to the application and supported frequency.

By selecting the most suitable connector according to the characteristics of the equipment and the usage environment and using it properly, it is possible to build a high-quality signal transmission and a highly reliable system. A deeper understanding of coaxial cable connectors will be of great help in the effective operation of electronic equipment and communication systems.