DUAL-BAND WLAN ANTENNA DESIGN BY CONTROLLING HIGHER ORDER MODE CHARACTERISTIC

Abstract

This article presents a new method for designing a dual-band WLAN antenna using the higher order harmonic mode of a monopole antenna, the first-order mode of which operates at the low-frequency band of WLAN (2.4 GHz). After measuring the current distribution in the higher order antenna mode, we added a stub in a location where the electric field is strong. This added stub brought the resonant frequency into the higher WLAN frequency band. Further, the input impedance was controlled by controlling the width of the branch without affecting the low-frequency band of the WLAN (the first-order mode of the monopole antenna). This compact dual-band antenna was designed to be the size of a universal serial bus dongle, and the -10 dB bandwidths are 700 MHz (2.3-3 GHz) at 2 GHz and 1 GHz (4.9-5.9 GHz) at 5 GHz, which cover the full WLAN dual bands. The proposed antenna achieves more than 50% efficiency in WLAN bands.