Miniaturization of patch antennas using arrays of split ring resonator type unit cells

Abstract

This paper presents the design and measurement of a miniaturized rectangular patch antenna incorporating split ring resonator (SRR) metamaterial. An array of 2×2 SRR unit cells is positioned beneath the patch layer. The proposed antenna maintains a low-cost planar structure, facilitating easy fabrication on a 1.43 mm thick FR4 board. Initially, a reference patch antenna is designed for operation at 2.44 GHz. Subsequently, an analysis of the SRR structure is introduced. The SRR structure exhibits negative permittivity at the resonance frequency, enabling the miniaturization of the patch antenna. Following optimization, both the reference and metamaterial-embedded patch antennas are fabricated and measured. Simulation results show good agreement with the experimental data. The metamaterial-embedded antenna demonstrates a –10 dB bandwidth of 66.1 MHz at 2.44 GHz. In comparison, the reference patch antenna measures 28.46 mm × 28.46 mm, whereas the proposed antenna has a reduced size of 22.7 mm × 22.7 mm, achieving a 36.4% area reduction. The proposed antenna is suitable for indoor usage, e.g., Bluetooth direction finding applications.