A BROADBAND PATCH ANTENNA BASED ON A PLANAR UNCLOSED ANNULAR RADIATOR

Abstract

Subject and Purpose. Results are presented of numerical simulation of a patch antenna in the form of a planar unclosed annular radiator placed above an earthed plane. The work has been aimed at optimizing the key parameters of the antenna, like the degree of its matching with external circuits, achievable through proper selection of the excitation method and variation of the substrate permittivity, antenna gain, and power and polarization characteristics. Methods and Methodology. The antenna has been designed as an unclosed annular strip line. The angular width of the gap in the ring was varied during the optimization process. The antenna is excited via a segment of a coplanar line. The numerical simulation was performed for the unclosed resonator model, with all the limitations imposed on the model in the framework of the finite element method. The performance characteristics of the antenna have been optimized with account of the return loss level, gain magnitude and ellipticity over the given frequency range. Results. Frequency and power characteristics of the patch antenna based on an unclosed annular strip-line radiator have been ana- lyzed and optimized over a broad frequency range. The impact of key parameters of the structure upon its performance characteristics has been established, specifically of the angular width of the gap in the unclosed ring, separation from the ground plane, and dielectric permittivity value in the substrate. The possibility has been demonstrated of generating radiation fields of an elliptical polarization which is rather close to circular. Conclusions. The frequency, spectral and power characteristics studied of a patch antenna built around a planar unclosed annu- lar strip-line radiator above an earthed plane. The numerical modeling was performed within the framework of the finite element method. The principal dependences of the antenna’s electrodynamic performance upon such parameters as geometry, characteristic dimensions and material constants have been condsidered. The results obtained allow suggesting application of such antennas in the capacity of both independent radiators and elements of phased antenna arrays.