Proximity-Coupled Microstrip Antenna for Bluetooth, WiMAX, and WLAN Applications

This letter presents a novel proximity-coupled multiband microstrip patch antenna. The proposed antenna simultaneously operates at Bluetooth (2.4-2.485 GHz), WiMAX (3.3–3.7 GHz), and WLAN (5.15–5.35 and 5.725–5.85 GHz) bands with consistent radiation pattern and uniform gain. The antenna is a two-layer design. A V-shaped patch with a rectangular strip on the top layer is fed by a buried rectangular strip in the middle layer by proximity coupling. Furthermore, resonating parasitic structures in the bottom plane are used to improve the antenna characteristics. The fabricated antenna has a small size of
$24 \times 27 \times 1.6~\hbox{mm}{^3}$
on an FR4 substrate.