A compact printed multistubs loaded resonator rectangular monopole antenna design for multiband wireless systems

摘要

In the present article, a compact triple-band multistubs loaded resonator printedrnmonopole antenna is proposed. The antenna consists of a quarter wavelength twornasymmetrical inverted L-shaped stubs to excite two resonant modes for 3.5/5.5 GHzrnbands and one integrated horizontally T-shaped stub with inverted long L-shapedrnstub to excite resonant mode for 2.5 GHz band. By loading these stub resonatorsrnalong y-axis with distinct gaps, the antenna resonates at three frequencies 2.57/3.52/rn5.51 GHz covering the desired bands while keeping compact size of 24 × 30 mm~2rn(0.2 λ_0 × 0.25 λ_0). The proposed antenna is fabricated on Rogers RT/duroid 5880rnsubstrate with thickness 0.79 mm and its performance experimentally verified. Thernmeasured results reveal that the antenna has the impedance bandwidths of about 210rnMHz (2.50-2.71 GHz), 260 MHz (3.37-3.63 GHz), and 650 MHz (5.20-5.85 GHz),rnfor 2.5/3.5/5.5 GHz WiMAX and 5.2/5.8 GHz WLAN band systems. The antennarnprovides omnidirectional radiation patterns and flat antenna gains over the three operatingrnbands. In addition, the design approach and effects of multistubs resonatorrnlengths on the operating bands are also examined and discussed in detail.