Abstract
This article proposes a dual mode dual-polarized antenna configuration for IRNSS and fifth generation
(5G) applications, operating at a frequency of 3.5 GHz based on characteristic mode analysis (CMA),
and aims to provide broadband dual-polarized functionality. The original design of the antenna is
a traditional patch antenna, and its dual-polarized features are determined using characteristic
mode analysis. The full-wave method is used to stimulate both orthogonal modes using a 50 Ω
coaxial input line at 3.5 GHz. In this design, the circular patch has been extended into an elliptical
patch through a process of mode separation. The circular patch exhibits resonance at a frequency
of 2.5 GHz, whereas the extended elliptical radiator demonstrates two resonance modes at 2.5 GHz
and 3.5 GHz. The operational mechanism is elucidated by modal analysis and characteristic angle.
This antenna operates on two different frequencies at the 2.5 GHz IRNSS band with horizontal
polarization and the 3.5 GHz 5G service with vertical polarization. The maximum gain achieved with
these frequency ranges is 5.31 dBi and 4.72 dBi, respectively. A ring resonator is chosen to improve
the axial ratio and impedance bandwidth of the suggested prototype. The antenna’s ground plane
is shaped like a rectangle and features a V-shaped slot in the radiating patch. The antenna’s physical
footprint is 50 mm × 50 mm × 1.6 mm and an FR4 dielectric substrate serves as its foundation.
Through its interaction with a PIN diode, the diode modifies the polarization of the antenna. The
antenna functions as a right-handed circular polarization (RHCP), when the diode is operational. The
bandwidth from 4.3 to 7.5 GHz is covered. On the other hand, it generates linear polarization (LP)
between 4.2 and 5.3 GHz. The experimental antenna is evaluated and examined for its performance
characteristics. The simulations are carried out utilizing the CST simulator. A prototype antenna has
been manufactured and its performance has been validated against simulated findings.