Vibration attenuation of a PCB enclosure in a radar system employing internal particle dampers

Abstract

Vibration can damage sensitive components and mountings on printed circuit boards (PCBs) within active electronically scanned array radar transmit/receive modules, which can result in reduced system performance and system failure. To solve this issue, a novel vibration reduction measure by incorporating particle dampers within the PCB enclosure is proposed. To install particle dampers, finite element-based modal analysis was performed to identify vibration-sensitive areas inside the structure. The dominant modal frequency was validated with a sinusoidal sweep test performed on a vibration shaker. Based on these results and spatial constraints, two cavities were created for particle damper installation: one near the sensitive area (damper A) and another farther away (damper B). Steel particles of varying sizes, i.e. 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, and 3.5 mm, were used to fill these cavities. Experimental investigations were conducted to evaluate the effect of particle size and filling ratio on peak vibration response under different acceleration loads. Both dampers achieved the best response reductions with a 2.5 mm particle size, though their critical filling ratios differed: 92% for damper A and 96% for damper B. The findings indicate an 89% and 64% reduction in acceleration response with dampers A and B, respectively. This novel method of integrating particle dampers within the housing enhances its vibration suppression capabilities and provides superior response reductions compared to the previous approach of mounting them on the periphery. Furthermore, the method is reliable even in elevated temperature environments due to the use of metallic particles.