10 - CAD Projects

Summary

Introduction

The present chapter describes a set of simulation or design exercises meant to apply, within a microwave Computer-Aided Design CAD environment, the concepts developed in the rest of the book. Each example is, potentially, a CAD laboratory trace. To allow the reader to replicate the examples, additional material is made available online in the form of a project in its specific CAD environment. We chose to develop the project on two well-known and widely used platforms, Microwave Office (MWO) [1] and ADS (Advanced Design Systems) [2]. To keep the presentation within reasonable limits (and also to avoid fast obsolescence due to the evolution of the CAD tool interfaces), for each example only a synthesis is provided with the main results in graphical form.

The examples closely follow the evolution of the text and are intended as short and tutorial in nature. Rather than reporting on full real-word designs, leading to a ready-togo layout, they concentrate on specific aspects that are dealt with in the text on a more theoretical equation-based level. All figures are directly copied (sometimes with minor changes and a conversion to black and white) from the CAD tool user interface, their graphical format being in a way a part of the design experience of the user. Some of the CAD projects actually provide a CAD implementation of numerical examples presented throughout the text.

Microstrip Line and Stub Matching of a Complex Load

The project proposes a CAD implementation of Example 2.5. A line plus stub section (the stub in short circuit) is set up to match to the impedance. The design frequency is chosen as 10 GHz. The electrical line length at 10 GHz is initially set equal to the approximate values found in Example 2.5, and a further optimization is carried out, obtaining slightly different values. Fig. 10.1 shows the resulting input impedance compared to the goal,.