Multipath-Coupling-Based Filtenna for Base-Station Applications

作者：Wang, Ji Wen; Ma, Ruyu^*; Bo, Shao Fei; Huang, Huifen; Zhang, Xiu Yin

来源：IEEE Transactions on Antennas and Propagation, 2023, 71(11): 8473-8482.

DOI：10.1109/TAP.2023.3306466

• Base station
• compact
• dual polarization
• filtenna
• filtering antenna
• high rejection
• inductively connected
• stacked patches
• wide stopband

In this study, a multipath-coupling-based filtenna with enhanced stopbands is proposed for 5G base-station applications. To simultaneously support multiple communication standards in a shared aperture, base-station antennas need a wide stopband with high rejection to maintain sufficient isolation from other operating frequencies. However, this usually requires filtennas to be designed with multiple radiation nulls, which makes the filtennas difficult to match. Therefore, without an additional impedance-matching circuit, it is challenging to achieve a filtenna with sufficient impedance matching in the passband, wide stopband, and high out-of-band rejection. To solve this problem, we propose a multipath-coupled filtenna with enhanced stopbands. The proposed filtenna consists of two stacked patch radiators connected by four metal strips, a crossed feeder, and four hooked strips. The wide stopband was obtained by four radiation nulls introduced by these structures. To improve the impedance matching in the passband, four metal strips were used to connect the two stacked patches to tune the coupling between them. Finally, a prototype was fabricated and measured. The measurement results show that the proposed filtenna has a passband of 3.3-3.8 GHz with an average gain of 8.9 dBi and an upper stopband up to 7 GHz with an out-of-band suppression more than 19 dB. The proposed filtenna is a good candidate for 5G n78 band (3.3-3.8 GHz) applications in base stations.