PCB-manufactured log-periodic dipole array for 0.5-20 GHz

This paper presents a wideband log-periodic dipole array (LPDA) antenna with operation frequency band from 500 MHz up to 20 GHz. The LPDA has 35 elements with maximum dimension restricted to 300 mm both in length and width of the array. The measured antenna has better than −10 dB reflection coefficient over the whole operation frequency band, and very stable 6.1 dBi realized gain in 4-20 GHz band, as confirmed by measurements. Effects of different surface finishes on manufactured printed circuit board (PCB) antennas have also been studied, but no significant differences have been found whether typical polymer solder mask or electroless nickel immersion gold (ENIG) finish is used to cover the high-frequency elements of the LPDA.