A High-Selectivity SIW-Based Filtering Antenna Based on Through-Glass Vias (TGVs)

This letter presents a filtering antenna (FA) integrating a patch radiator with a third-order substrate integrated waveguide (SIW) bandpass filter, achieving high selectivity and wide bandwidth for Ka-band applications based on through-glass vias (TGVs). The proposed design introduces five radiation nulls, significantly enhancing out-of-band suppression and spectral selectivity. A prototype was fabricated and tested to validate the design. Measurements demonstrate a −10 dB impedance bandwidth from 29.04 GHz to 36.7 GHz, corresponding to a relative bandwidth of 23.3%, with stable in-band gain exceeding 3.42 dBi and a peak gain of 5.23 dBi at 31.5 GHz. The antenna achieves suppression levels of 20.53 dB and 20.03 dB in the high and low-frequency stopbands, respectively, and exhibits steep attenuation rates on both sides of the passband.