Low-Profile Wideband High-Gain Folded Dipole Antenna

Abstract

A low-profile broadband folded dipole antenna with high gain is presented in this letter. Folded dipole antenna is utilized to reduce the height of the reflector to 0.1λ, without degrading the impedance bandwidth. Parasitic patches shorted to the reflector are employed to reduce the gain variation of the antenna. The |S ₁₁ | ≤ $-$10 dB bandwidth of the antenna is from 1.18 to 4.08 GHz (110$\%$) with a broadside gain of 9.25 ± 1.25 dBi over the bandwidth of 1.27-4.03 GHz (103.8$\%$). The radiation pattern variation of the antenna is small over the bandwidth. The cross-polar level is below $-$25 dB from 1.18 to 3.4 GHz. The dimensions of the antenna are 0.78λ × 0.78λ × 0.10λ, where λ corresponds to the lowest frequency.