Asymmetric Folded Dipole Antenna With High Front-to-Back Ratio for LTE Base Stations

In this letter, a broadband asymmetric folded dipole antenna with high front-to-back ratio (FBR) for LTE base stations is proposed. The proposed antenna consists of asymmetric folded dipoles, a planar hook-shaped microstripline, and a square metal reflector. By loading an appropriate circular aperture on the reflector, the back radiation of the antenna is effectively reduced, thereby improving the FBR. At S
₁₁
= -15 dB, the simulated and measured impedance bandwidth of the proposed antenna is 58.2% (1.62-2.95 GHz) and 52.1% (1.66-2.83 GHz), respectively. The antenna exhibits desired unidirectional radiation pattern with half-power beamwidth greater than 65 ° at both principal planes and FBR from 18.6 to 25 dB in the frequency range of interest, 1.7-2.7 GHz. Also, it has an average gain of 7.5 dBi.