How to Improve the Reliability of SMA Connectors

1. Introduction

RF coaxial connectors are widely used in radar, remote control equipment, satellite communications, and other systems operating in the microwave frequency range. As signal transmission components, their performance directly affects the quality of transmitted signals. Given their extensive use in these systems, each connector must exhibit high reliability to meet overall system reliability requirements.

For connectors operating in harsh environments with strong vibrations and high-impact conditions, even higher reliability is required. Enhancing the operational reliability of these connectors has become an urgent problem that needs to be addressed. Based on real-world applications, this study selects a typical RF coaxial connector, the SMA type, for analysis. The goal is to identify a rational approach to improving connector reliability that minimizes human influence.

2. Theoretical Analysis

RF coaxial connectors have two main performance indicators: Voltage Standing Wave Ratio (VSWR) and loss. Among these, VSWR has the most significant impact on signal transmission performance and must be strictly controlled within a specific range.

The quality of the connector’s mating directly affects the VSWR parameter. Therefore, it is crucial to strictly control the diameter ratio of the inner and outer conductors, ensuring that the mating pin and socket fit well without deformation. This keeps electrical performance deviations within tolerance limits.

3. Measures to Improve Reliability

To enhance the reliability of these connectors in harsh environments, the following measures can be implemented:

Use High-Quality Connectors – Manufacturing quality directly affects connection quality, so selecting high-quality, well-manufactured connectors is essential.

Regular Cleaning and Maintenance – Proper maintenance helps protect the plating and ensures reliable electrical contact. To improve corrosion resistance, it is recommended to use gold-plated inner conductors.

Use Torque Wrenches – Applying a preset torque wrench helps resolve the contradiction between anti-loosening requirements and electrical performance parameters, preventing damage caused by human factors.

For miniaturized connectors, which have lower anti-loosening reliability and weaker structural strength, this technique provides an effective solution.

4. Conclusion

The study confirms that the primary structural factor affecting electrical performance degradation is deformation of the mating pin and socket. Before the torque value reaches a level that negatively impacts VSWR, no significant correlation between torque and VSWR is observed. Therefore, it is recommended to use torque wrenches during assembly to eliminate human errors and improve the reliability of RF coaxial connectors in harsh environments.