Читать книгу Fundamentals of Terahertz Devices and Applications - Группа авторов - Страница 36

For automotive radar applications at 70 GHz, we need to design an elliptical lens antenna with a directivity of 30 dB fed by a rectangular waveguide as shown in the figure. The waveguide can be modeled considering the field in the aperture is approximated by the TE10 mode.

1 Make a study of the optimal dimensions of the waveguide and the lens to reach the specifications for the following different lens materials: materials: silicon (εr = 11.9), quartz (εr = 4) and plastic (εr = 2)

2 How does the change physical dimensions with the lens dielectric material?

3 How does the critical angle change with the lens dielectric material? And the directivity inside the dielectric and the reflection efficiency of the optimized waveguide feed?

4 How does the radiated patterns by the several lens antenna compared to each other?

Justify your answers with figures and try to give a physical insight into the problem.