Synthesis and analysis of dielectric
bifocal lenses
V. A. Kaloshin 1, Huu Duc Nghiem 2
1Kotelnikov Institute of
Radioengineering and Electronics of Russian Academy of Sciences, Mokhovaya str., 11- 7,
Moscow 12509, Russia
2 Moscow Institute of Physics
and Technology (State University), Institutskiy per. 9,
Dolgoprudny, Moscow.
region., 141700, Russia
The paper is received on August 8, 2018
Abstract. A technique is developed for the synthesis of dielectric bifocal lenses
that convert two divergent cylindrical waves into convergent or flat ones. The
technique is based on the well-known approach with setting the initial portion
of the lens surface and sequentially finding other areas. The technique ensures
the smoothness of the obtained solution. As an example, we synthesized three
variants of bifocal lenses with different sets of parameters and an analysis of
their aberrations. Analysis of aberrations showed that the lens, which forms
flat fronts at the output, has a mean-square aberration of 1.25.10-4,
and for a lens with symmetrical focal curves it is 1.5.10-3.Using
the finite element method, a numerical study of the scanning characteristics of
a planar bifocal lens antenna was carried out.
A numerical experiment was performed to
confirm the scanning properties of the synthesized lenses. A cylindrical
dielectric bifocal antenna with a width of 160 mm and a height of 3.4 mm was
located inside a planar metal waveguide of the same height and was excited by
an H- sectorial horn with an input section of 7.2 × 3.4 mm and an output
cross-section of 13 × 3.4 mm at a frequency of 37.5 GHz. The geometry of the
focal curve was obtained by optimization by the criterion of maximum gain. In
this case, the direction of the axis of the horn radiator was also optimized.
Losses in metal and dielectric were not taken into account in the calculation.
The antenna efficiency is more than 0.8 in the sector of angles ± 25 degrees,
which considerably exceeds the sector of angles between the directions of
formation of ideal flat fronts (± 13 degrees).
Key words:
dielectric lenses, bifocal lenses, planar lenses,
aberrations, scanning.
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For citation:
V. A. Kaloshin, Huu Duc Nghiem. Synthesis and analysis of dielectric
bifocal lenses.
Zhurnal Radioelektroniki - Journal of
Radio Electronics. 2018. No. 8. Available at
http://jre.cplire.ru/jre/aug18/17/text.pdf
DOI
10.30898/1684-1719.2018.8.17