The advancement of technologies in antenna's world
stimulates growing new demands to get better antenna performance on the design
process for all components, including radome. Radar Dome, or usually called
Radome is a dielectric material which is placed over the antenna for protection
from its physical environment. In this case, the energy radiated by the antenna
must pass through the radome. In most cases, some amount of radiated energy is
dissipated as it passes through the antenna radome. This dissipated energy
reduces the effective gain of the antenna and causes several effects, such as
boresight error, changing antenna side lobe level and depolarisation. To
achieve higher gains, dielectric radome with antennas as the source constitutes
a relevant solution. The current technique used composite or layered materials
like Teflon, Polyethylene and Quartz to suppress the reflection of the radiated
energy but, it makes the fabrication more complicated and highly cost. Figure 1
shows the construction of patch antenna enclosed by a radome[1].
Even though the antenna may
be carefully designed to have low sidelobes and high radiation efficiency, a
poorly designed radome can degrade its performance seriously. Typically, the
radomes are fabricated of a thickness of a dielectric material, wherein the
thickness is one-half wavelength at a mid-band frequency of operation for the
antenna. The composite or layered dielectric radomes are frequently required in
practise to protect antenna systems against environmental conditions. However,
the complicated manufacturing process inevitably introduces errors into the
material properties of the composites, which tend to degrade the electromagnetic
(EM) performance of radome. In conclusion, an optimum chosen material and
construction design of radome are the key importance to focus through
analytical technique to improve the antenna performance.
Written by Nuraiza Ismail and Rina Abdullah
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