Ultra-Wideband Dual-Polarized Antenna With Three Resonant Modes for 2G/3G/4G/5G Communication Systems

In this paper, a compact dual-polarized ultra-wideband dipole antenna is realized by exciting three resonant modes using double-loop (DL) dipoles with stepped exponential-shaped (ES) arms. First, a single-loop (SL) crossed dipole antenna using the modified direct feeding (MDF) structure with ES arms is designed and analyzed to achieve wide bandwidth (1.7-2.7 GHz) with two resonant modes. Second, without increasing the volume of the antenna, one more loop is employed to gain one more resonant mode to enhance the bandwidth into 1.68-3.7 GHz and fractional bandwidth (FBW) up to 75% for VSWR <; 1.5. In order to adjust three resonant modes independently, the ES arms of the DL dipole antenna are designed in stepped shapes. The HPBW is 65-70° for 1.7-2.7 GHz (2G/3G/4G) and 95° for 3.4-3.6 GHz (5G). In addition, the proposed antenna can also be designed with a bandwidth of 2.38-6.42 GHz (FBW of 92%) for VSWR <; 2, occupying WLAN/4G/5G. As demonstrations, the proposed antennas covering 1.68-3.7 GHz for VSWR <; 1.5 (Antenna A) and 2.38-6.42 GHz for VSWR <; 2 (Antenna B) are designed, fabricated and measured, and the measured results agree well with the simulations.