A Printed Log-Periodic Tree-Dipole Antenna (Plptda)

Abstract—A miniaturized printed log-periodic fractal dipole antenna is proposed. Tree fractal structure is introduced in an antenna design and evolves the traditional Euclidean log-periodic dipole array into the log-periodic second-iteration tree-dipole array (LPT2DA) for the first time. Main parameters and characteristics of the proposed antenna are discussed. A fabricated proof-of-concept prototype of the proposed antenna is etched on a FR4 substrate with a relative permittivity of 4.4 and volume of 490mm × 245mm × 1.5mm. The impedance bandwidth (measured VSWR < 2) of the fabricated antenna with approximate 40 % reduction of traditional log-periodic dipole antenna is from 0.37 to 3.55GHz with a ratio of about 9.59: 1. Both numerical and experimental results show that the proposed antenna has stable directional radiation patterns and apparently miniaturized effect, which are suitable for various ultra-wideband applications. 1.