A Dual-Band Dual-Polarized Stacked Microstrip Antenna with High-Isolation and Band-Notch Characteristics for 5G Microcell Communications

A dual-band dual-polarized stacked microstrip antenna with high-isolation and band-notch characteristics is proposed. The proposed antenna is comprised of three layers of substrate. To obtain high isolation between two input ports, a pair of orthogonal differentially driven feeding lines are printed on the top side of the bottom layer. To yield the desired lower- and upper-frequency bandwidths for 5G microcell communications, two sets of 2\times 2 radiating patch arrays are printed on the second and top layer substrates, respectively. Compared with the conventional microstrip antenna, besides demonstrating a smaller size of 0.48\times 0.48\times 0.085\,\,\lambda -{0}^{3} , the proposed antenna has also exhibited higher isolation of better than 40 dB and higher gain of >8 dBi. Finally, a novel technique of arranging four meander lines that connects the four array elements printed on the second layer substrate is proposed to achieve an adjustable band-notch characteristic.