Design of DGS Based Stacked T-Shaped Quad Band Antenna for WLAN/WiMAX Applications

The proposed design presents a planar monopole antenna that operates in a quad-band range for S-band, Wi-MAX, and WLAN applications. It is excited by a microstrip line feed. A radiating element made up of stacked T-shaped strips on the substrate's zenith surface and a ground plane with a defective structure on the underside are features of this antenna. Individual tuning of the antenna's resonance frequencies is possible by varying the length of the strips. The dimensions of the antenna prototype are $50 x 35 x 0.508 ~\text{mm}^{3}$. The measured results show that the proposed antenna exhibits four different operating bands with a return loss less than 10 dB - at frequencies of $2.2 \text{GHz}, 2.8 \text{GHz}, 3.8 \text{GHz}$, and 4.8 GHz(from 2.1 to 2.35 GHz), corresponding to the following frequency ranges: $2.6-3.18 \text{GHz}(550 \text{MHz}), 3.5-4.58 \text{GHz}(470$ MHz), and 3.77-7.70 GHz (3930 MHz). These bands are suitable for key wireless communication standards, like Wi-MAX (3.3-3.8 GHz and 5.25-5.85 GHz) and WLAN (2.4-2.5 GHz, 5.1-5.3 GHz, and 5.72-5.85 GHz). The first two bands, operating in S-band, are suitable for Wi-MAX, while the third and fourth bands can be deployed for WLAN (3.6/4.9 GHz) and Wi-MAX applications. Additionally, the projected antenna demonstrates excellent radiation patterns and satisfactory gains across all operating bands. The design process and parametric analysis were carried out using the HFSS simulation software, and the antenna was fabricated on an FR-4 substrate.