Abstract:
Antennas have a wide range of applications in different fields. Some of the antennas are designed
for airborne communications while some antennas have vehicular, signal intelligence and ISR
(intelligence, surveillance and reconnaissance) applications. Certain antennas are designed for
specific applications, which are suitable for particular purpose, but a number of antennas are
multi performing and are versatile. These antennas have a number of feeding techniques. For
instance microstrip line feeding, microstrip inset line feeding, coaxial line feeding, aperture
coupled feeding and proximity coupled feeding line.
In this research project, proximity coupled feeding technique is applied. A circularly polarized
stacked dual band microstrip patch antenna is designed with a cavity backed feeding substrate. In
order to get the resonances, the width and length of upper and lower patch is varied. In addition,
two stacked patches provide good impedance matching. The feeding line and cavity in the
ground plays a pivotal role in getting the required resonances of interest at the desired bands of
frequency. The measured results of the fabricated prototype comply with the simulated results.
The dual band stacked patch antenna gives 5.19dBi and 5.59dBi gain at 1.75 GHz and 2.38 GHz
respectively. The antenna efficiency is 90% and 75% at both these bands with stable radiation
patterns.
