Design of a printed log-periodic dipole array for ultra-wideband applications

A printed Log-periodic dipole array (LPDA) is presented, operating over the C, X and Ku bands. The antenna feeding structure consists of two coaxial cables, in order to realize an in¯nite balun which provides the required broadband input matching. The second coaxial cable mirrors the ¯rst one, connected to the antenna input, and is capable of both stabilizing the antenna phase center and improving the radiation pattern. The antenna has been designed using CST Microwave Studio, with an useful frequency range of 4{18 GHz. Moreover, both simulated and measured results show that the proposed LPDA can be successfully used as an Ultra Wideband Antenna in the range 4.25{13.25 GHz, in which its phase center remains stable