A novel filtering patch antenna with high selectivity and wide out‐of‐band suppression

Abstract

In this study, a novel filtering patch antenna with high selectivity and wide out‐of‐band suppression is presented. The antenna consists of a square patch, a metal ground and a feeding line, and four radiation nulls are introduced out of the passband. By designing the stepped feeding line with metal vias, two radiation nulls are introduced out of the passband. A U‐shaped slot is etched on the ground, and a third radiation null is produced. A lowpass filter, integrated into the feeding line, results in the fourth radiation null and the harmonic suppression response. By introducing these structures, the antenna achieves satisfactory frequency selectivity and bilateral wide harmonic suppressions. The proposed design is verified by the simulation and measurement results. Measured impedance bandwidth is 15% (3.33–3.87 GHz), which can perfectly cover the 5G‐N78 band, and measured peak gain can reach 9.0 dBi. The measured edge roll‐off rates in the lower and upper sidebands are 232 and 139 dB/GHz, respectively.