Differentially Fed, Dual-Band Dual-Polarized Filtering Antenna With High Selectivity for 5G Sub-6 GHz Base Station Applications

• Published in: IEEE transactions on antennas and propagation Vol. 68; no. 4; pp. 3231 - 3236
• Main Authors: Li, Yapeng, Zhao, Zhipeng, Tang, Zhaoyang, Yin, Yingzeng
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 5G mobile communication; Antenna arrays; Antenna feeds; Antennas; Bandpass filters; Base station antenna; Circuits; differentially fed; Dual band; Dual polarization (waves); dual-polarized antenna; filtering antenna; high selectivity; Microstrip transmission lines; Resonant frequency; Selectivity; Slot antennas
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2019.2957720

In this communication, a novel dual-band dual-polarized filtering antenna with high selectivity is proposed. By etching four slots at each side of a square radiating patch, dual operation bands as well as a natural radiation null between the two bands are observed. Another two radiation nulls are generated by introducing a novel feeding structure, which is composed of a microstrip line with open-circuit stepped-impedance resonators (OCSIRs). Thus, a dual-band bandpass filtering response of the realized gain is obtained. Each polarization of the antenna is differentially fed, and the differential port isolation is better than 37 dB. A prototype of the antenna element and a <inline-formula> <tex-math notation="LaTeX">1\times 4 </tex-math></inline-formula> array is fabricated and tested to validate our design. Measured results show that the antenna element has dual operation bands of 3.28-3.71 and 4.8-5.18 GHz for VSWR < 1.5. Besides, a high out-of-band gain-suppression level which reaches 17.7 dB is also obtained. Good performance of the proposed antenna makes it a promising candidate for 5G sub-6 GHz base station systems.