Achieving Wider Impedance Bandwidth Using FullWavelength Dipoles

This paper investigates the use of full-wavelength dipoles (FWD) to achieve wider bandwidth than halfwavelength dipoles (HWD). Two dual-polarized antennas are built based on FWDs for base station applications as examples. The first antenna is an isolated cross-dipole employing two FWDs with simple configuration. It is able to cover the lower band for cellular communication from 698 to 960 MHz. The second antenna has four FWDs arranged in a square loop array form and tightly coupled with each other. The employed full-wavelength dipoles are bent upward to maintain a small aperture size, so that the realized element still fits in traditional base station antenna (BSA) array. The antenna can be matched across the band from 1.65 to 3.7 GHz, which can cover both the 3G/4G band from 1.7 to 2.7 GHz and the 5G (sub-6 GHz) band from 3.3 to 3.6 GHz simultaneously. By comparing the attained antennas with comparable antennas based on HWDs, it demonstrates a fact that, when fed properly, FWDs exhibit wider bandwidth than HWDs, and the available methods to improve the bandwidth of HWDs can also be used on FWDs.