A New Coupler Concept for Contactless High-Speed Data Transmission Monitoring

This paper presents a new concept of a coupler that can be applied to high-speed data transmission contactless measurements. The proposed approach is dedicated for differential signal transmission monitoring in microstrip coupled lines on printed circuit boards (PCBs). The coupler, produced on a separate PCB, is overlayed on the transmission line with the differential signal and delivers decoupled differential signal to the main measurement path. The main advantage of this solution is that no dedicated connectors are required for the measurement process, which results in product cost reduction and design simplification. The complete design methodology of the proposed coupler has been described. Theoretical considerations have been confirmed by the example coupler prototype that was fabricated and measured. The measurement results show that the proposed concept may be advantageous for contactless signal monitoring in widely used high-speed interconnections realized on cheap FR-4 PCBs.