A compact dual band antenna based on metamaterial-inspired split ring structure and hexagonal complementary split-ring resonator for ISM/WiMAX/WLAN applications

A miniaturized dual-band antenna is proposed for industrial scientific and medical (ISM), worldwide interoperability for microwave access (WiMAX), and wireless local area network (WLAN) applications. The proposed antenna consists of hexagonal complementary split-ring resonator (HCSRR), metamaterial-inspired split-ring structure, and a partial ground plane. The prototype antenna is fed by 50-Ω microstrip feed line, which is printed on a 30 × 30 × 0.8 mm3 FR-4 substrate. HCSRR in the radiating element is used to create a new resonance at 2.4 GHz for achieving dual-band characteristics. A split in the outer hexagonal ring induces a magnetic resonance which leads to improvement of the bandwidth of the antenna. The proposed antenna is fabricated and measured. The measured -10-dB impedance bandwidths are 180 MHz (2.42–2.60 GHz) and 2400 MHz (3.44–5.84 GHz) with a resonance frequency of 2.56 GHz and 4.64 GHz, respectively, which is suitable for ISM, WiMAX, and WLAN applications. Analysis of HCSRR is discussed in detail using empirical design equation with metamaterial property. The prototype antenna has suitable radiation characteristics for all resonance frequencies.