Английская Википедия:Extended hemispherical lens

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The extended hemispherical lens is a commonly used lens for millimeter-wave electromagnetic radiation. Such lenses are typically fabricated from dielectric materials such as Teflon or silicon. The geometry consists of a hemisphere of radius Шаблон:Mvar on a cylinder of length Шаблон:Mvar, with the same radius.

Scanning performance

When a feed element is placed a distance Шаблон:Mvar off the central axis, then the main beam will be steered an angle Шаблон:Mvar off-axis. The relation between Шаблон:Mvar and Шаблон:Mvar can be determined from geometrical optics:[1]

<math> \frac{d}{L} = \tan \gamma. </math>

This relation is used when designing focal plane arrays to be used with the extended hemispherical lens.

See also

References

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