Design of Bow-tie Microstrip Antenna with Fractal Shape for W-Lan Application

In this paper, we presented the design and analysis of Bow-Tie antenna on FR4 substrate, which is suitable for the WLAN2.4GHz application. A novel Koch-like fractal curve is proposed to transform Ultra-Wideband (UWB) bow-tie into so called Koch-like sided fractal bow-tie dipole. The fractal bow-tie dipole can operate in multiband with moderate gain (3.5-7dBi) and high efficiency (60%-80%), which is corresponding to certain shape parameters, such as notch ratio α, notch angle φ, and base angles θ of the isosceles triangle. Compared with conventional bow-tie dipole and Koch-like fractal with the same size, this fractal-like antenna has almost the same operating properties in low frequency and better radiation pattern in high frequency in multi-band operation, which makes it a better candidate for application of WLAN and other communication systems. It’s well known that bow-tie antenna is a planar form of UWB finite biconical antenna. It is a practical angle-dependent frequency independent antenna. Because of its ultra-broadband, light weight, thin profile configurations, low cost and easiness of fabrication, reliability and conformability, bow-tie antenna has been widely studied and used in engineering applications. Also, the simple geometries make it compatible to be connected to planar feeding system in an integrated architecture. The novel Koch-like sided bow-tie dipole can behave both like multiband and UWB with conspicuous advantages over its conventional counterpart, printed dipole and Sierpinski gasket in dimension, bandwidth, gain and efficiency, which makes it a good choice for applications of UWB, PCS, WLAN, WiFi, WiMAX, and other communication systems. Details of the antenna design and simulated results return loss, Input impedance, Radiation Patterns, E-Field, H-Field and Current Distributions, VSWR are presented and discussed. The proposed antenna is simulated at 2.4 GHz using An soft HFSS-11.