A Planar Compact Helical Log-Periodic Array

Abstract

A novel compact log-periodic array antenna is proposed in this paper. It employs printed planar helical dipoles as its elements. The size of this array antenna is only 58% of a conventional log-periodic dipole array (LPDA). Thus, the proposed antenna shows advantages of compact structure and ease of fabrication. A prototype is fabricated and tested. Measured results show that an impedance bandwidth from 1.87 GHz to 5.89 GHz (3.15:1) for VSWR <; 2 is obtained. The gain of the antenna is better than 5.73 dBi with a maximum value of 7.63 dBi over the whole band.