QuinStar Technology’s QLA series lens antennas are
available with apertures ranging from 2 to 18 inches (50-457.2 mm) for any frequency in
the 12-220 GHz range. These antennas consist of a lens which is fed (illuminated) by a
specially-designed feed horn. They have inherently low sidelobes, particularly in
comparison to Cassegrain reflector antennas, as there is no blockage of the main beam by a
subreflector or feed structure.
Specially designed
lenses when combined with high performance feeds produce high gain, precise beam patterns
and efficiency comparable to the best reflector antennas, even at high millimeter wave
frequencies. They operate over a fairly wide frequency range, which is generally
determined by the characteristics of the input feed horn.
Standard antennas
are focused at infinity (far field). However, custom designs focused at a finite range,
generally 2 to 300 inches (0.05 to 10 meters) from the lens, can be provided. They can
also be produced at a fairly low cost in large quantity. In addition, the antenna housing
can be used as an enclosure for other components, system electronics or the entire system. |
The length of the antenna is nearly equal to its lens diameter (f/D = 1) to
achieve a reasonable size with optimal performance, although other f/D ratios are
available as special products. The feed horn for these antenna may be either conical
(standard product) or scaler feed horn (symmetrical, low side lobe).
Typical lenses
have a smooth external surface and operate virtually independent of frequency. However,
for specific narrowband applications, the lens can be zoned to reduce size and weight. To
construct a large (12" - 40"), lightweight lens with a reasonable and
appropriate focal length QuinStar offers a Fresnel lens for narrow band applications.
The interface to
these antennas is a circular waveguide of suitable diameter for the center frequency.
However, an integral circular-to-rectangular waveguide transition is available as well as
a variety of other options including a detachable circular-to-rectangular transition,
orthomode transducer (OMT), circular polarizer (fixed or adjustable). QuinStar can also
provide antennas with dual-polarization capability and dual-frequency band operations as
customized products. |
