ORIGINAL RESEARCH article
Front. Phys.
Sec. Interdisciplinary Physics
Volume 13 - 2025 | doi: 10.3389/fphy.2025.1637651
This article is part of the Research TopicRF Multi-Mode Circuit Theory and TechnologyView all articles
Miniaturized Dual-Band Bandpass Filter With Closely Spaced Passbands and Wide Stopband
Provisionally accepted
- Nanjing Normal University, Nanjing, China
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This work presents a new miniaturized dual-band bandpass filter (BPF) featuring closely spaced passbands and wide stopband performance. The filter is designed on a slots-loaded substrate integrated waveguide (SIW) cavity fed by microstrip line. By introducing a longitudinal rectangular slot at the cavity's center symmetry line and two transverse rectangular slots at the upper and lower edges, two shorted patches are formed within the SIW. A second-order BPF is constructed through the gap coupling. Subsequently, two quarter-wavelength resonators are introduced into the upper and lower transverse slots, which are respectively coupled with two shorted patches. This configuration allows the second-order filtering passband, formed by shorted patches coupling, to be split into two second-order closed passbands with frequency ratio of 1:1.04. Due to the low harmonic characteristics of the shorted patches, the designed dual-band BPF achieves a -20 dB stopband range of up to 2.86f0. Finally, a prototype is designed, fabricated, and measured to validate the proposed design, demonstrating good consistency between the simulated and measured results.
Keywords: bandpass filter, shorted patch, slots-loaded, substrate integrated waveguide (SIW), Wide stopband
Received: 29 May 2025; Accepted: 23 Jun 2025.
Copyright: © 2025 Li, Ni, Li, Han, Tian, Li and Ma. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Tianye Ma, Nanjing Normal University, Nanjing, China
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