A wide band log periodic millimeter-wave antenna for 5G femtocells applications

A wide band log periodic millimeter-wave antenna is proposed for 5G femtocells applications. This log periodic antenna consists of circular patches with radius kept up at a proportion of scaling factor tau=1.05. The proposed antenna prototype is designed and simulated at a frequency range of 25 to 35.5 GHz with a fractional bandwidth of 34.73%. This proposed antenna exhibits low return loss at all frequency bands such as 26, 27.5, 29, 30, 32, 33, 35, and 38.1 GHz with reflection coefficient values such as -13.41,-29.07,-30.9,-23.11,-11.29,-11.44,-12.47, and -10.01 dB including almost 101% radiation efficiency and attained maximum gain values such as 11.36,10.86,10.83,11.31,9.88,9.19,11.5, and 12.36 dBi. Over the entire frequency band, the proposed antenna exhibits right-hand circular polarization with an axial ratio of under 3 dB. Furthermore, the antenna is fabricated and measured the results where there is a better agreement with simulated results. This type of low-profile antenna can be applicable for femto base stations for 5G communications.