OVERVIEW

In addition to the more visible advantages of printed structures, which have already been stated in the previous chapter, there is another one that was not so obvious in the early years; accurate and time-efficient designing of such circuits has become possible through the use of full-wave electromagnetic simulation tools. For instance, a microstrip matching network for input and output of a transistor amplifier can be simulated by replacing the active devices with suitable signal terminals. This would provide a very accurate model of the matching circuit. Then, the device model of the transistor is inserted between the terminals in a circuit simulator and overall circuit response of the amplifier is obtained. In essence, this is the approach that is used by a microwave engineer today. One should be able to anticipate the overall response very accurately by using this approach provided that good models for the active circuits are available. Note that all interactions between the matching circuit sections, as well as radiation and other higher-order effects, are automatically taken into account during the simulation process. Hence, use of full-wave electromagnetic simulation tools changed the design methodology in microwave engineering for good. Once regarded as black magic, microwave engineering has been placed in extremely well-defined design principles, if not simplified, by the help of computer simulation tools, which is the promoted philosophy through this book.

Full-wave computer simulations significantly reduce the trial and error in microwave engineering. However, as is always repeatedly indicated, no simulation tool can replace...