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

摘要

In this article, the authors proposed an eight-element linear array of fractalantennas for dedicated short range communication (DSRC; 5.9 GHz) serviceband. The single element of the array is a newly proposed fractal antennawhose radiating patch is derived from the Fibonacci series with the incorporationof Koch snowflake, and it poses a 2D quadrantal symmetry. The gain ofthe structure is improved by down shifting the radiating patch with respect toits ground plane. The feed network of the array is designed in such a mannerto make the structure compact as well as to use the advantage of array mutualcoupling for improving the array radiation pattern. The fabricated single elementgives 7.54 dB gain and 128 MHz bandwidth with a radiation efficiency ofη = 85.11%. The prototype array gives 15.18 dB gain with 105 MHz bandwidthand radiation efficiency of η = 72.12%. The measured cross-polarization ofsingle element and the array along the direction of the main beam are lessthan −80 dB and −60 dB, respectively, in both the xz- and yz-plane. Both singleelement and the array are capable of satisfying the bandwidth requirementsfor DSRC applications.