A Miniatured Passive Low-Pass Filter With Ultrawide Stopband Based on 3-D Integration Technology

• Published in: IEEE microwave and wireless components letters Vol. 32; no. 1; pp. 29 - 32
• Main Authors: Yin, Xiangkun, Wang, Fengjuan, Lu, Qijun, Liu, Xiaoxian, Liu, Yang, Yang, Yintang
• Format: Journal Article
• Language: English
• Published: IEEE 01.01.2022
• Subjects: 3-D integrated circuit; Capacitors; Inductance; Inductors; low-pass filter (LPF); lumped elements; Microwave circuits; Microwave integrated circuits; Spirals; through-silicon via (TSV); Through-silicon vias
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2021.3115607

By using integrated lumped elements based on through-silicon via (TSV) technology, a 3-D low-pass filter (LPF) with ultracompact size and ultrawide stopband is proposed. The 3-D magnetic coupling is enhanced between microsize spiral inductors to increase the mutual inductance and improve the high-frequency performance. A coaxial TSV with enhanced capacitance in high resistivity silicon (HRS) is utilized both as capacitor and as a vertical interconnection without any overhead in area and routing. The 3-D nature of the proposed filter yields a miniaturized size of <inline-formula> <tex-math notation="LaTeX">0.2\times0.10 </tex-math></inline-formula> mm 2 . The LPF is analyzed with equivalent circuit model and validated with the well-matched <inline-formula> <tex-math notation="LaTeX">S </tex-math></inline-formula>-parameters obtained by finite element method simulation and measurement. With −3-dB cutoff frequency at 2.6 GHz, the LPF exhibits an insertion loss below 1 dB, a reflection loss over 17 dB in the passband, and a suppression level over 20 dB from 5.28 up to 40 GHz in the stopband.