A Miniaturized Wideband SIR Interdigital Bandpass Filter With High Performance Based on TSV Technology for W-Band Application

In this letter, an ultra-compact wideband stepped impedance resonators’ (SIR) interdigital bandpass filter (IBPF) is proposed based on through-silicon via (TSV) and three-dimensional integrated circuit (3-D IC) technology. SIR structure can achieve higher coupling strength at a small impedance ratio. On this basis, the IBPF is designed by exploiting
$\lambda $
/4 SIR; the proposed filter is realized with compact size and far parasitic passband and exhibits superior fractional bandwidth (FBW) and out-of-band suppression characteristics. Based on the transformation of the Chebyshev low-pass circuit model, a seventh-order IBPF centered at 98.5 GHz is obtained. An improved method combining TSV technology with the coupling coefficient method is proposed, which simplifies the design process and improves the influence of parasitic inductance on the design process. The FBW of SIR IBPF based on TSV is 40%, the insertion loss is less than 1.3 dB, and a reflection of better than 30 dB in the passband. The size of the compact SIR IBPF is only
$0.24\times0.7$
mm2 (
$0.28\times 0.79\lambda _{g}^{2}$
).