A Compact Triple Band Antenna Based on Multiple Split-Ring Resonators for Wireless Applications

Abstract

In this paper, a compact multi-split-ring resonator-based antenna is presented for wireless applications. The proposed antenna integrates multiple resonators to achieve multiband operation, where each resonator corresponds to a specific frequency band. A theoretical analysis is conducted to model the equivalent circuit of the proposed antenna, followed by an analytical study to calculate the resonant frequency of each resonator. By integrating these resonators, the proposed antenna achieves a compact size of 23 × 24 × 1.6 mm3 (0.19 × 0.2 × 0.01λ3), resulting in a size reduction of 81.6% compared to a conventional patch antenna, while maintaining gain, improving bandwidth, and providing excellent impedance matching. The proposed antenna covers the 2.4–2.8 GHz (14.55%), 3.25–3.75 GHz (14.28%) and 4.5–7.84 GHz (54.13%) frequency bands, providing acceptable gains of 1.5 dBi, 2 dBi and 3.2 dBi, respectively. The antenna was designed with CST, its performance was verified with HFSS simulations and it was validated with an equivalent circuit in ADS. Finally, the antenna was fabricated to confirm the accuracy and reliability of the simulation results, and it was found that the measurements agreed well with the simulations. This multiband functionality, combined with a compact form factor and simple feed line, makes the antenna cost-effective, easy to manufacture and suitable for various wireless communication applications, including 5G sub-6 GHz mid-band (2.5/3.5/5/5 GHz), RFID (2.45/5.8 GHz), WiMAX (2.4/3.5/5.8 GHz), Wi-Fi 5/6/6E (2.4/5/6 GHz) and WLAN (5.2/5.8 GHz).