Compact Dual-Band Base-Station Antenna Using Filtering Elements

This communication presents a compact dual-band dual-polarized filtering antenna for base-station applications. The proposed dual-band antenna consists of a high-band (HB) dipole element and a low-band (LB) patch element, both with filtering responses. The HB element is embedded into the LB element, minimizing the overall size. The strong mutual coupling between the HB and LB elements is reduced by employing filtering HB and LB elements. For demonstration, a prototype of the dual-band antenna operating at LTE band 41 (2.5–2.7 GHz) as well as LTE bands 42 and 43 (3.3–3.8 GHz) is fabricated and measured. The antenna features a compact size of 41
$\times\,\,41$
mm
²
(
$0.52\,\,\lambda _{hh} \,\,\times0.52\,\,\lambda _{hh}$
, where
$\lambda _{hh}$
denotes the guided wavelength at the highest frequency of HB). The cross-band isolation is higher than 27 dB without using extra filtering or decoupling circuits. In addition, a measured average gain of 7.8 dBi in LB and 7.7 dBi in HB is achieved. These merits make the proposed antenna suitable for 5G multiband aperture-shared array application.