Dual-Band Dual-Polarized Antenna Using a Simple Radiation Restoration and Decoupling Structure

This letter presents a simple structure dual-band dual-polarized antenna. The higher-band (HB) antenna is located coaxially under the lower-band (LB) one to save the installation space. The blocking effects of the LB antenna seriously deteriorate the HB antenna's radiation patterns. To solve this problem, we first introduced four stacked patches to restore the radiation performance. Unfortunately, using the stacked patches, the isolation between the LB and HB antennas reduces from about 25 to 20 dB. Then, we introduced four C-shaped metal strips as the decoupling structure and the isolation improves from 20 dB to more than 30 dB within a wideband. These stacked patches and metal strips are printed on top and bottom sides of the LB antenna substrate and therefore no extra substrate layer is needed. For demonstration, a prototype of the dual-band antenna operating at 1710–2690 MHz (LB) and 4200–5000 MHz (HB) is implemented. Normal directional radiation patterns are obtained with stable in-band gains of 7.5 and 9.5 dBi. Better than 33 dB measured isolation between the LB and HB antennas is realized.