Design of compact dual-band shared-aperture antenna system based on frequency selective surface

A miniaturized dual-band dual-polarization base station antenna array operating at 2.4-2.8 and 4.6-5.0 GHz is proposed in this paper. The upper-band unit is embedded in the lower-band unit to miniature the array size. The size of the proposed shared-aperture antenna element is 0.28 x 0.28 lambda L ${{\rm{\lambda }}}_{L}$. To ensure the normal radiation of dual-band under the small frequency ratio, a meander slot frequency selective surface structure is introduced, which is electromagnetically transparent to the lower-band unit and function as metal ground for the upper-band unit to ensure the normal radiation of the upper and lower-band units, respectively. Simulation and measured results show that the antenna array meets the following design specifications: dual-band operating (voltage standing wave ratio [VSWR] < 2), mutual coupling less than -20 dB basically, satisfactory gain and radiation characteristics.