W-Band Substrate Integrated Waveguide IPD Bandpass Filters Using Through Glass via Technology

This article proposes a series of glass-based substrate integrated waveguide (SIW) filters featured with high selectivity, low loss, and small size for W-band communication systems. The through glass via (TGV) process is detailed explored for integrated passive device (IPD) SIW structure implementation. To achieve the sharp roll-off, a novel SIW doublet with two poles and two transmission zeros (TZs) is realized by using both TE202 and TE401 modes as resonant modes in a single TGV-based SIW cavity. Based on this, an improved diagonal coupled box-like fourth-order topology is innovatively introduced, and a fourth-order SIW filter with quasi-elliptic function response is realized. To further miniaturize the circuit size of the doublet, an alternative approach is presented using dual-mode SIW resonator based on the TE101 and TE201 modes with perturbed metallization vias. This leads to form a doublet with a TZ in the upper stopband, and the parameter sensitivity analysis of the resonator is also conducted. Finally, two W-band fourth-order TGV-based IPD filters are designed, manufactured, and tested. The measured insertion losses of the on-wafer filters are 1.62 and 1.28 dB, respectively.