Electronic products such as telecommunication systems, computers, and digital consumer electronics have come to require high-speed and high-density packaging. High-frequency electromagnetic field analysis is used for the printed-circuit board design of these products. For the analysis of the GHz-frequency characteristics of antennas, filters, resistors, capacitors, inductors and passive elements in wiring patterns, electromagnetic field analysis has proven to be suitable for the measurement well. However, a printed-circuit board is a large collection of interconnects, and even if a high-end personal computer is used, the analysis takes several days at least. Therefore, before fabrication, albeit is impossible to verify various aspects of the electromagnetic field analysis. Generally, if the analysis time has to be shortened from days to minutes, the subdivision modeling technique is used. In this case, the high-frequency analysis accuracy is unsatisfactory. In this paper we propose instead an accurate electromagnetic field solver for high-frequency characterization as a subdivision modeling technique using an EOSE (Enhanced Optimized Segment Extraction) method with multi-port S-parameter consideration of the coupling between transmission lines, based on the original, OSE (Optimized Segment Extraction) method. We evaluated this EOSE method for analysis time and high-frequency analysis accuracy in a multilayer printed-circuit board with via connections. The analysis time was confirmed to be about 1/6 that of the result analyzed in the whole of the structure. Furthermore, the analytic precision error was within 0.5 dB in the 5–8 GHz range when dividing in the continuous part of the transmission line. From these results, we showed the validity of this proposal technique.

View full abstract

Wire-grid polarizing films have been used intensively as parts of the displays of liquid crystal TVs, liquid crystal projectors, and personal computers. Wire-grid polarizing films have metal wires and whose width is less than the wave length of light. The incident light having perpendicular polarization to the wire pass through the wire-grid polarizing films and the light of parallel polarization reflects, Since silver has the highest reflectance in metal, the efficiency of recycle use of reflected light on the Ag-WGPOLARIZER is expected to be the highest among other metals.
With a cyanide-free bath, we damascene electrodeposited silver into trenches 145 nm wide and 175 nm deep. The silver deposited on the film was then partly removed using ion milling and metal wires were fabricated. The reflectance of S-polarization is inversely related to the amount of voids in the trenches. Smaller current density and a larger amount of Na₂S₂O₃ decrease the amount of voids and hence increase the reflectance of S-polarization.

View full abstract