Printed double-dipole antenna with high directivity using a new feeding structure

In this study, a planar printed double-dipole antenna with broadband performance and high directivity is presented. The proposed antenna consists of two dipole elements, two pairs of parallel striplines and a microstrip balun. The main features of the designed antenna are the two dipole elements designed with different lengths and excited in the left and right parts with a pair of antiphase signals. The two dipole elements are designed with different lengths for achieving broadband performance. High directivity is obtained by feeding the two dipole elements with the two antiphase signals. In order to illustrate the effectiveness of the proposed design, a prototype of the proposed antenna is fabricated and measured. Experimental results of the fabricated antenna have verified the effectiveness of the proposed design. Measured results show that the fabricated antenna provides a 53.7% impedance bandwidth ranging from 4.5 to 7.8 GHz and a measured gain better than 4 dBi. Good unidirectional radiation patterns with a high front-to-back ratio greater than 17 dB are achieved.