Point-to-multipoint gigabit backplane design

This paper describes the implementation of a contactless midplane as part of Nortel XA-Core project. The design is intended to allow for 1 Gb/s per link across a 36 inch backplane using point to multipoint configuration. Each link provides communication between a driving card and up to 10 receiving cards which can be hot-plugged-in. The transmission system uses DC blocking to achieve bus isolation by means of PCB coupler structures optimized to guarantee a BER better than 1E-14 based on a receiving signal as low as 30 mV. This novel VSOC (viaed short/open couplers) design is presented in the paper. Extensive simulations and signal integrity analysis have been the key to achieve a working midplane under worst-case conditions.