High-gain and circularly polarized fractal antenna array for dedicated short range communication systems

Abstract

In this paper, a low-profile fractal antenna and its array for DSRC-band applications have been proposed. The proposed single element is a newly designed fractal antenna which is right-handed circularly polarized (RHCP) and derived from the Koch-snowflake 1st-iteration. Moreover, a diagonal slot defect in the ground plane has been implemented for resonating the structure at the desired frequency and, to get a low cross-polarization over the operating frequency. The compact feed-network of the array is designed using a Wilkinson power-divider. A single element and a 4 × 1 antenna array are designed, prototyped, and verified. The antenna array is designed by a single-layer microstrip structure with a compact size of 151.70 × 43.50 mm2 . According to the experimental results, the single element and the antenna array have S11 of −15.27 dB and −13.95 dB, and RHCP gain of 6.14 dBic and 11.98 dBic, respectively. Moreover, the computed radiation efficiencies of of single element and array are 78.17% and 71.50%, respectively, while CP bandwidths of single element and array are 49.00 MHz and 58.00 MHz, respectively. The performance of the proposed RHCP antenna is suitable for the DSRC-band application.