Absorptive Filtering Packaging Antenna Design Based on Through-Glass Vias

This article presents a design of Ka -band absorptive filtering packaging antenna (AFPA) based on through-glass vias (TGVs). Compared to other reflective filtering antennas (RFAs), the AFPA showcases a distinct design featuring dual absorptive band-edge radiation nulls and four reflective stopband radiation nulls. Additionally, the AFPA used a glass multilayer stacked 3-D package scheme that enables good microwave characteristics and high-density interconnects. The radiating patch was composed of an RFA and band-stop filter (BSF) whose reflection coefficients were almost complimentary. The RFA radiating patch and BSF unit were comprised of defect microstrip structure (DMS) and defect ground structure (DGS), corresponding dimensions were
$\lambda _{g}$
/4 and
$\lambda _{g}$
/2, respectively. The radiating patch layer was connected to the substrate-integrated waveguide (SIW) feeding structure layer through a glass transition layer with TGVs and pads, and the packaging process was accomplished using laser bonding. Then we used SIW operating in Ka -band to feed the AFPA. To validate this design, a prototype of the AFPA was fabricated and measured. The results indicate −10 dB impedance bandwidth ranging from 30 to 35 GHz, with a peak gain of 6.06 dBi and a maximum radiation efficiency of approximately 85%. The measurements reveal that the AFPA has dual absorptive band-edge radiation nulls at 30.9 and 33.5 GHz, and four reflective stopband radiation nulls at 25.9, 27.3, 35.1, and 38.4 GHz, with a suppression level exceeding 15.5 dB.