Modeling and optimization of high-frequency/high-speed microelectronic devices and systems are important for achieving next generation information technology and communication systems.Increasing circuit size and design complexity,coupled with stringent design specifications and shorter design cycles,demand tools that are faster,more accurate and automated than possible today.Electromagnetic(EM)/physics-based design accuracies will be needed not only at the component level,but also at the circuit and system levels.Models with EM/physics-oriented accuracy but without the computational exponso of direct EM/physics simulations are necessary.Recent applications of neural networks and space mapping for microwave design lead to new modeling and Computer-aided Design(CAD)with potential advantages in both speed and accuracy.Applications are being made in modeling and design of microstrip and CPW circuits,multilayer interconnects,embedded passives,printed antennas,LTCC circuits,semiconductor devices,measurement standards,filters,amplifiers,mixers and so on.New CAD methods for optimization,statistical design,global modeling,and computational electromagnetics exploiting computational intelligence concepts are being developed.Advanced microwave CAD methodologies such as knowledge-aided design,knowledge-based neural networks,and space mapping are being developed.This leads to new opportunities combining equivalent circuit/empirical models,EM/physics simulation,behavioral modeling,neural network and space mapping optimization algorithms for fast and accurate design of high-frequency components and systems.