부산대학교 도서관

In this letter, a low-cost and compact ±45° dual-polarized patch antenna array suitable for 5G massive multiple-input–multiple-output (MIMO) base station is proposed. The antenna unit comprises a microstrip patch and a parasitic patch in a stacked configuration. The two patches can be directly connected by four metallic sheets using surface-mounted technology, and these sheets are formed by bending branches achieved from grooving the upper parasitic patch. The loading of vertical metal baffles at the upper patch can shrink the antenna planar size and broaden the beamwidth simultaneously. The upper patch with bent branches can be formed in a piece by sheet metal technology, while the lower patch is printed on the substrate along with the feed network of the antenna array. A 1 × 3 antenna array with a unit size of 0.343 λ L × 0.343 λ L × 0.071 λ L ( λ L is the wavelength at 3.28 GHz) is fabricated and measured. It attains a bandwidth of 20.3% (3.28–4.02 GHz) with | S 11 | < −15 dB and | S 21 | < −17 dB. The measured realized gain is 11.2 ± 0.3 dBi. The half-power beamwidth is 74 ± 5°, and the cross-polarization is below −24 dB. The measured envelop correlation coefficient is lower than 0.007.