ABSTRACT This letter presents a high‐selectivity fourth‐order W‐band Substrate Integrated Waveguide (SIW) bandpass filter, realized using wafer‐level Through Glass Via (TGV) technology. To achieve steep out‐of‐band rejection, extracted‐pole resonator and singlet resonator technologies are adopted to generate two asymmetric transmission zeros (TZs) flanking the passband, significantly enhancing frequency selectivity. Furthermore, a novel micro‐hole array structure is introduced on the metallization layers to effectively mitigate thermal stress, a common challenge in large‐area glass processing. The fabricated prototype, centered at 86.9 GHz, demonstrates a passband from 84.3 to 89.1 GHz with an insertion loss of less than 2.6 dB. The excellent agreement between measured and simulated results validates the design methodology, offering a highly competitive filtering solution for integrated W‐band communication and radar systems.
Yu et al. (Mon,) studied this question.