Ultra-wideband planar patch antenna array using multimode resonant antenna element for millimeter-wave applications

This letter proposes an ultra-wideband planar patch antenna array in a millimeter wave (mmW) band. The radiation element consists of a pair of symmetrical E-shaped patches and two pairs of grounded metallic vias. A microstrip line is selected to excite the antenna element through an H-shaped coupling slot. The entire structure is designed on two substrates, which makes it have a relatively low cost. The periodic boundaries are adopted in element simulation to achieve good agreement of performances between the element and the final array. The proposed element exhibits triple-resonant characteristics and achieves a working bandwidth of 62%. By employing the proposed element, an 8 x 8 array with a 1-to-64 full-corporate feeding network is designed, manufactured, and measured. The measured results demonstrate that the fabricated array prototype realizes an impedance bandwidth of 71% from 22 to 46.3 GHz covering all 5G mmW bands in the K/Ka band, a gain from 18.2 to 23.4 dBi over the whole operating bandwidth, and cross-polarization levels below -30 dB. With the merits of an ultra-wideband, stable radiation, and a low cost, the proposed array can be applied to long-distance mmW communications and related applications.