2       Rectangular Waveguides

Waveguides are transmission lines commonly used in electronics, especially in higher frequency ranges like microwaves. A waveguide can be simply described as a metal pipe usually filled with air.

This tutorial is dedicated to rectangular waveguides and contains all basic information concerning their operation rules. All the interesting features are visualised using electromagnetic simulation with QuickWave software.

All examples used here were prepared in free CAD QW-Modeller for QuickWave and the models preparation procedure are described. All examples considered herein are included in the QW-Modeller and QuickWave STUDENT Release installation as both, QW-Modeller and QW-Editor projects.

The following topics are included:

• Wave propagation in rectangular waveguide

• Waveguide mode

• Higher order modes

• Wavelength in a waveguide

• Propagation below the cutoff frequency

The model preparation procedure in QW-Modeller is described in the following chapter:

·      Project preparation wr340 - a rectangular waveguide WR-340 filled with air, excited with a fundamental TE₁₀ mode and terminated with a load port matched to the waveguide.