RF Coaxial Relay Reliability Problems Solved

摘要

Raytheon has been at the forefront in developing test methodologies and automated test equipment to ensure high reliability RF coaxial relays are employed in our communications systems. Our systematic approach has clearly demonstrated that the long-term reliability can be predicted primarily by the DC performance. We automated the DC parametric test operations while simultaneously maximizing the sensitivity, repeatability, and throughput. We developed a methodology for accurately measuring contact resistance over temperature utilizing very low voltages and currents (20mv, 100ua). This allows us to simulate receive level signals, detect intermittent parts, and ultimately determine the reliability of the components. The test set increases test throughput, reduces labor, verifies new designs prior to production and automatically detects design, assembly, adjustment, and manual testing errors. Our process has been accepted by one major supplier and we subsequently have been able to procure 2300 SPDT high reliability coaxial relays for a cruise missile program with zero system failures. We have also qualified and procured numerous transfer style RF coaxial relays for airborne applications. It is common knowledge that RF coaxial relay users continue to struggle to find reliable parts for their applications. One unexpected outcome is that our unique test methodology and equipment allow us to readily identify unreliable RF coaxial relay designs. It appears that due to the lack of standards in testing many of the supplier's catalogs have been found to inaccurately depict their products performance.