Hybrid frequency/time domain field theory based CAD of microwave circuits

In this paper we report the first successful combination of a frequency domain CAD program, namely OSA90/hopeTM, with a time domain TLM electromagnetic field simulator running on various hardware platforms. The technique allows optimization of microwave structures using time domain field analysis without the need for equivalent circuits or lookup tables. A comparison of the execution speed of the TLM field simulator on a number of computers, from IBM PCs to workstations to massively parallel computers have been made. This provides a clear picture of the required CPU time for performing such simulations on various hardware platforms. A detailed account of the hybrid frequency/time domain procedures, advantages and disadvantages of combining the frequency and time domain methods as well as parallel programming techniques on the DECmpp 12000 with a view towards future hybrid domain CAD/CAM systems are given. The principal application is field-based hybrid domain modeling of complex microwave and millimeter wave structures.