Design, simulation and measurement techniques for embedded decoupling capacitors in multi-GHz packages/PCBs
Embedded capacitor is a better solution than surface mount capacitors for decoupling in a high speed, high performance packages/PCBs. Our study has showed that with conventional approaches, the embedded capacitor for decoupling in power delivering network can work from 100 MHz to 1 GHz systems. Pushing the operating frequency over 1 GHz is a challenge for system designers. This paper discusses the embedded decoupling capacitor design for multi-GHz systems through principles, simulation, measurement error, and error elimination.
Materials options for dielectrics in integrated capacitors
Value requirements for capacitors in modern microelectronic assemblies extend over six orders of magnitude from about 1 pF to 1 /spl mu/F. For many applications this entire range must be present on the same substrate with the lower end providing a variety of filtering, timing, RF and A/D purposes and the upper end serving decoupling and other energy-storage functions. The smaller capacitors generally require stricter tolerances and tighter stabilities than the larger units. There are many candidate dielectric materials, deposition/etching processes and plate configurations for integrating these devices. It is difficult, if not impossible, for any single dielectric material and capacitor configuration to provide this entire range without either the highest or lowest-valued components occupying too large an area, exhibiting excessively high series resistance, or being too small to fabricate with acceptable tolerance. Therefore, it will often be necessary to mix integrated capacitor technologies on a single substrate. BCB, polyimide and SiO/sub 2/ provide a small enough capacitance and sufficient tolerance for the bottom end of the range while anodized metals or ferroelectric powders in epoxy thin films can cover decoupling termination and some energy storage into the range of hundreds of nF. Ferroelectric thin films provide much higher dielectric constants but are currently difficult to integrate, especially for small values, and have less temperature, frequency and bias stability than paraelectrics. Once it becomes possible to form ferroelectric thin films at temperatures low enough for organic substrates these films will be very useful for energy storage.
Far-field dispersal modeling for fuel-air-explosive devices
A computer model for simulating the explosive dispersal of a fuel agent in the far-field regime is described and is applied to a wide variety of initial conditions to judge their effect upon the resulting fuel/air cloud. This work was directed toward modeling the dispersal process associated with Fuel-Air-Explosives devices. The far-field dispersal regime is taken to be that time after the initial burster charge detonation in which the shock forces no longer dominate the flow field and initial canister and fuel mass breakup has occurred. The model was applied to a low vapor pressure fuel, a high vapor pressure fuel and a solid fuel. A strong dependence of the final cloud characteristics upon the initial droplet size distribution was demonstrated. The predicted fuel-air clouds were highly non-uniform in concentration. 18 refs., 86 figs., 4 tabs.