Modeling of High-speed Printed Circuit Board Abstract This thesis is an exercise to investigate the various methods of creating an equivalent circuit model for a high-speed digital printed circuit board (PCB)

This thesis is an exercise to investigate the various methods of creating an equivalent circuit model for a high-speed digital printed circuit board (PCB) assembly and to perform computer simulation on such a system. The term highspeed printed circuit board is widely accepted in the engineering community to be refering to PCB which is applied to digital system with operating frequency in excess of 100MHz and transition period of signal (rise time and fall time) less than a nanosecond. Such a digital system can often be found in computer motherboard, plug-in card and communication network card. Due to the high operating frequency and rapid signal transition rate, harmonics up to gigahertz range can often exist during operation. Every physical aspects of the printed circuit board assembly including the components and all metallic structures have to be carefully considered in order for such a system to function properly. A structural approach to modeling the PCB assembly is adopted. The assembly is considered as an integration of parts such as integrated circuits, sockets, connectors, printed circuit board traces, cables, vias, power supply, power planes and discrete components including resistors and capacitors. The structural approach assigns an equivalent circuit to each of the components described above in terms of linear and non-linear circuit elements. The equivalent circuits can be lumped or distributed as in the case of transmission lines. These equivalent circuits are then linked together to form a complete equivalent circuit for a digital printed circuit board assembly. Computer simulation is subsequently performed using commercial SPICE circuit simulator and characteristics of the system can be studied. The range of validity for the equivalent circuit models considered in this thesis is restricted from d.c. to 5GHz or where quasi-TEM approximation applies, whichever is lower. This range is sufficient for present day digital systems with operating frequency not exceeding 500MHz. Methods for derivation of equivalent circuits can be divided into three categories, i.e. through theoritical analysis, through field solution employing