Understanding the Different Types of Coaxial Cables Used with SMA Connectors

SMA connectors are a popular choice for high-frequency applications due to their durability, performance, and ease of use. These connectors are commonly used with coaxial cables, which are designed to transmit high-frequency signals with low loss of signal quality. However, not all coaxial cables are created equal, and choosing the right cable for your SMA connector can significantly impact the performance of your system. In this article, we will explore the different types of coaxial cables used with SMA connectors, their characteristics, and how to choose the right cable for your application.

Types of Coaxial Cables Used with SMA Connectors

There are several types of coaxial cables used with SMA connectors, each with its own characteristics and advantages. The most common types of coaxial cables used with SMA connectors are:

• RG-58: RG-58 is a 50-ohm coaxial cable that is commonly used in low-power applications such as radio communications and amateur radio. It has a solid center conductor and a braided shield, which provides excellent flexibility and durability. RG-58 has a loss factor of around 0.6 dB per meter at 100 MHz and is suitable for frequencies up to 1 GHz.
• RG-174: RG-174 is a 50-ohm coaxial cable that is commonly used in microwave and wireless applications. It has a smaller diameter than RG-58, which makes it more flexible and easier to work with in tight spaces. RG-174 has a loss factor of around 2.3 dB per meter at 1 GHz and is suitable for frequencies up to 2 GHz.
• RG-316: RG-316 is a 50-ohm coaxial cable that is commonly used in high-frequency applications such as GPS, cellular, and satellite communications. It has a small diameter, which makes it ideal for applications where space is limited. RG-316 has a loss factor of around 5.7 dB per meter at 2 GHz and is suitable for frequencies up to 12 GHz.
• Semi-Rigid: Semi-rigid coaxial cables are used in high-frequency applications where maximum performance is required. These cables have a solid outer conductor and a solid inner conductor, which provide excellent shielding and low loss. Semi-rigid cables are available in various diameters and are suitable for frequencies up to 50 GHz.

Characteristics of Coaxial Cables Used with SMA Connectors

When choosing a coaxial cable for your SMA connector, several characteristics need to be considered to ensure optimal performance. These characteristics include:

1. Impedance: Impedance is the resistance of a cable to the flow of electrical current. SMA connectors are designed to work with 50-ohm coaxial cables, so it's essential to choose a cable with the same impedance to prevent signal reflections and loss of signal quality.
2. Capacitance: Capacitance is the ability of a cable to store electrical charge. Coaxial cables with high capacitance can cause signal distortion and loss of signal quality, especially at high frequencies.
3. Attenuation: Attenuation is the loss of signal strength as it travels through a cable. Coaxial cables with high attenuation can cause signal loss and reduce the range of your system.
4. Velocity of propagation: Velocity of propagation is the speed at which a signal travels through a cable. Coaxial cables with a high velocity of propagation can cause signal distortion and loss of signal quality, especially at high frequencies.

Choosing the Right Coaxial Cable for Your SMA Connector

When choosing a coaxial cable for your SMA connector, several factors need to be considered. These include:

• Frequency: The frequency range of your system will determine the type of coaxial cable you need. For low-frequency applications, such as radio communications, RG-58 is a suitable choice. For higher frequency applications, such as microwave and wireless, RG-174 or RG-316 may be more appropriate. For maximum performance, semi-rigid coaxial cables may be required.
• Power: The power level of your system will also determine the type of coaxial cable you need. For low-power applications, such as radio communications, RG-58 is a suitable choice. For higher power applications, such as cellular and satellite communications, RG-316 or semi-rigid coaxial cables may be required.
• Length: The length of your cable will also impact the performance of your system. Coaxial cables with high attenuation can cause signal loss over long distances, so it's important to choose a cable with low attenuation for long cable runs.

Conclusion

Choosing the right coaxial cable for your SMA connector is essential to ensure optimal performance of your system. The type of coaxial cable you choose will depend on several factors, including the frequency range, power level, and length of your system. By understanding the different types of coaxial cables used with SMA connectors and their characteristics, you can make an informed decision and choose a cable that meets the specific requirements of your application.