HORN-LENS ANTENNA FOR A TERAHERTZ REGION

Abstract

Like optical lenses, lens antennas allow the conversion of a spherical wave into a 
plane wave. It is known that if a spherical wave source is placed at the focal point of a lens, 
the wave passing through the lens is transformed into a family of parallel rays, which forms 
a flat front, due to successive refractions. However, the lens corrects not only the phase 
distribution in the pinhole, but also changes the amplitude distribution of the incident field 
due to the refraction of the lens. As a result, the input and output field structures of the lens 
differ, and the degree of difference depends on its profile, which causes additional losses in 
the waveguide. 
Lens antennas are widely used in antenna technology in ultra-high frequency bands. 
UHF antenna lenses should be well aligned with the surrounding area and have low thermal 
losses. The radiator ensures the distribution of the required amplitude of the electromagnet
ic field in the lens aperture. As in mirror antennas, the feed must have a point phase center 
and provide the necessary radiation polarization. 
The working principle of lens antennas is taken from optics. It consists of a point 
source, the spherical wave front of which is transformed into a plane front of the electro
magnetic wave of radiation. Due to this, it is possible to obtain a flat intra-phase gap of the 
required size and form a narrow directivity diagram. 
This work considers a lens antenna placed at the output of a dielectric channel-type 
waveguide. A metal-dielectric waveguide (MDI) with a square section is used as the main 
waveguide.