A Patch Filtenna With High Out‐of‐Band Suppression Levels

ABSTRACT A patch filtenna with high out‐of‐band suppression levels is presented in this letter. The proposed antenna is configured with a parasitic patch and a driven patch fed by a rectangular strip connected to a vertical coaxial probe. Etching four rectangular slots on the rhombus‐shaped driven patch can introduce a high‐frequency radiation null. One open rectangular ring connected to the rectangular feeding strip will produce a low‐frequency radiation null and introduce a resonance mode, making the operating bandwidth wider. Meanwhile, the parasitic patch is placed above the driven patch further to improve the impedance bandwidth and the high‐frequency filtering performance. The designed filtenna is 0.62 λ 0 × 0.62 λ 0 × 0.13 λ 0 , where λ 0 is the free space wavelength at the center frequency. The measured prototype demonstrates that the proposed antenna has a flat gain of 7.9 ± 0.4 dBi over the −10‐dB fractional bandwidth of 12.4% from 2.05 to 2.32 GHz, as well as a high suppression level of 26.1 and 20.6 dB at low‐ and high‐frequency out‐band. These advantages make the antenna suitable for 5G n34 band communication systems.