Physics:Extended hemispherical lens
From HandWiki
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 R on a cylinder of length L, with the same radius.
Scanning performance
When a feed element is placed a distance d off the central axis, then the main beam will be steered an angle γ off-axis. The relation between d and γ can be determined from geometrical optics:[1]
- [math]\displaystyle{ \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
- ↑ Frid, Henrik (2016). "Closed-Form Relation Between the Scan Angle and Feed Position for Extended Hemispherical Lenses Based on Ray Tracing". IEEE Antennas and Wireless Propagation Letters 15: 1963. doi:10.1109/LAWP.2016.2545858. Bibcode: 2016IAWPL..15.1963F.
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