Compact microstrip fractal Koch slot antenna with ELC coupling load for triple band application

In this paper a novel triple band compact microstrip slot antenna is designed, utilizing fractal Koch shape based on metamaterial electric-LC element coupling load. The antenna is fed by CPW line, and it has triple band resonances operating at frequencies of about 1.5, 3.5 and 5.4 GHz for GPS, WiMAX and WLAN applications. The bandwidth of antenna at aforementioned frequencies is about 1.9%, 14% and 5% with the gains of −4.5, 3.75 and 5.3 dBi respectively. Also it has property of circular polarization for WiMAX application at 3.5 GHz. Furthermore metamaterial ELC element based on the metasurface theory, and making variation of the current distribution for circular polarization, made a compact small antenna at 1.5 GHz, where the antenna size is reduced to λ/5 × λ/5 through coupling on ELC element. The total size of the fractal antenna is assumed 40 × 40 mm, and is designed and fabricated on FR-4. The simulation results are extracted by HFSS commercial software, and compared with experimental results.