Dah-Weih Duan

Distributed effects of a gap in power/ground planes

A signal line running between two PCB power/ground planes, with one of the planes having a gap (split), was analyzed using full-wave electromagnetic tools. The gap inductance and the mutual coupling caused by the gap were examined, and distributed effects were observed. As a conclusion, a gap should always be AC-shorted, preferably in the immediate vicinity of critical signal lines.

Transponder packaging techniques in radio frequency identification systems

Packaging of RFID transponders at microwave frequencies requires unique materials and innovative methods in order to provide functional, reliable, and inexpensive transponders. Presented are two packaging methods-chip-on-board (COB) and chip-in-board (CIB)-that allow designers to utilize the existing semiconductor infrastructure to achieve a reliable microwave transponder and provide high volume manufacturing capabilities. The CIB technique allows for a thin outline transponder with a unique form factor. For both methods the tag package includes a single chip integrated circuit, a small resonant antenna, chip attach, wire bonding, chip encapsulation, and various substrate materials.