Design of a linear array of fractal antennas with high directivity and low cross‐polarization for dedicated short range communication application

Abstract

In this article, the authors proposed an eight-element linear array of fractal antennas for dedicated short range communication (DSRC; 5.9 GHz) service band. The single element of the array is a newly proposed fractal antenna whose radiating patch is derived from the Fibonacci series with the incorporation of Koch snowflake, and it poses a 2D quadrantal symmetry. The gain of the structure is improved by down shifting the radiating patch with respect to its ground plane. The feed network of the array is designed in such a manner to make the structure compact as well as to use the advantage of array mutual coupling for improving the array radiation pattern. The fabricated single element gives 7.54 dB gain and 128 MHz bandwidth with a radiation efficiency of η = 85.11%. The prototype array gives 15.18 dB gain with 105 MHz bandwidth and radiation efficiency of η = 72.12%. The measured cross-polarization of single element and the array along the direction of the main beam are less than −80 dB and −60 dB, respectively, in both the xz- and yz-plane. Both single element and the array are capable of satisfying the bandwidth requirements for DSRC applications.