Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression

Abstract This paper presents a novel dual-band bandpass filter (BPF) with two-port all-frequency reflectionless characteristics and enhanced upper-band suppression. The design integrates a square ring resonator (SRR) and advanced coupled lines (CLs), incorporating complementary absorptive branches t...

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Main Authors: Gangxiong Wu, Yang Jin, Wei Zhang, Ruirui Jiang, Jin Shi
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-025-06780-6
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author Gangxiong Wu
Yang Jin
Wei Zhang
Ruirui Jiang
Jin Shi
author_facet Gangxiong Wu
Yang Jin
Wei Zhang
Ruirui Jiang
Jin Shi
author_sort Gangxiong Wu
collection DOAJ
description Abstract This paper presents a novel dual-band bandpass filter (BPF) with two-port all-frequency reflectionless characteristics and enhanced upper-band suppression. The design integrates a square ring resonator (SRR) and advanced coupled lines (CLs), incorporating complementary absorptive branches to achieve broadband reflectionless performance. To mitigate upper-band harmonics, radial-stub-loaded resonators (RSLSs) with high-impedance transmission lines (HITLs) are introduced, extending suppression up to 10f 0 without significantly increasing the circuit footprint. A comprehensive theoretical analysis, including parametric studies and transmission zero (TZ) derivation, is conducted to optimize performance. Two prototypes are designed, fabricated, and tested: Prototype I achieves dual-band operation with all-frequency absorption, while Prototype II further enhances harmonic suppression. Experimental results closely align with simulations, with Prototype I exhibiting 3-dB fractional bandwidths (FBWs) of 19.5% and 9.7% at 1.38 GHz and 2.63 GHz, respectively, with insertion losses (ILs) of 0.95 dB and 1.47 dB. Prototype II achieves superior harmonic suppression, with attenuation levels of 22.8 dB over 2.9–20 GHz and 28.5 dB within 3.0–12 GHz. These designs offer high selectivity, inter-band isolation exceeding 45 dB, and full-spectrum absorption, providing an efficient solution for modern RF and wireless communication systems.
format Article
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publishDate 2025-07-01
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spelling doaj-art-dd792187587e490d98dba70515cdb36c2025-08-20T03:03:24ZengNature PortfolioScientific Reports2045-23222025-07-0115111110.1038/s41598-025-06780-6Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppressionGangxiong Wu0Yang Jin1Wei Zhang2Ruirui Jiang3Jin Shi4School of Information Science and Technology, Nantong UniversitySchool of Microelectronics and Integrated Circuits, Nantong UniversitySchool of Information Science and Technology, Nantong UniversitySchool of Information Science and Technology, Nantong UniversitySchool of Information Science and Technology, Nantong UniversityAbstract This paper presents a novel dual-band bandpass filter (BPF) with two-port all-frequency reflectionless characteristics and enhanced upper-band suppression. The design integrates a square ring resonator (SRR) and advanced coupled lines (CLs), incorporating complementary absorptive branches to achieve broadband reflectionless performance. To mitigate upper-band harmonics, radial-stub-loaded resonators (RSLSs) with high-impedance transmission lines (HITLs) are introduced, extending suppression up to 10f 0 without significantly increasing the circuit footprint. A comprehensive theoretical analysis, including parametric studies and transmission zero (TZ) derivation, is conducted to optimize performance. Two prototypes are designed, fabricated, and tested: Prototype I achieves dual-band operation with all-frequency absorption, while Prototype II further enhances harmonic suppression. Experimental results closely align with simulations, with Prototype I exhibiting 3-dB fractional bandwidths (FBWs) of 19.5% and 9.7% at 1.38 GHz and 2.63 GHz, respectively, with insertion losses (ILs) of 0.95 dB and 1.47 dB. Prototype II achieves superior harmonic suppression, with attenuation levels of 22.8 dB over 2.9–20 GHz and 28.5 dB within 3.0–12 GHz. These designs offer high selectivity, inter-band isolation exceeding 45 dB, and full-spectrum absorption, providing an efficient solution for modern RF and wireless communication systems.https://doi.org/10.1038/s41598-025-06780-6Dual-bandAbsorptive bandpass filter (ABPF)Upper-band suppressionsReflectionless
spellingShingle Gangxiong Wu
Yang Jin
Wei Zhang
Ruirui Jiang
Jin Shi
Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
Scientific Reports
Dual-band
Absorptive bandpass filter (ABPF)
Upper-band suppressions
Reflectionless
title Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
title_full Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
title_fullStr Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
title_full_unstemmed Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
title_short Dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
title_sort dual band bandpass filters with full band reflectionless response and enhanced upper stopband suppression
topic Dual-band
Absorptive bandpass filter (ABPF)
Upper-band suppressions
Reflectionless
url https://doi.org/10.1038/s41598-025-06780-6
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AT yangjin dualbandbandpassfilterswithfullbandreflectionlessresponseandenhancedupperstopbandsuppression
AT weizhang dualbandbandpassfilterswithfullbandreflectionlessresponseandenhancedupperstopbandsuppression
AT ruiruijiang dualbandbandpassfilterswithfullbandreflectionlessresponseandenhancedupperstopbandsuppression
AT jinshi dualbandbandpassfilterswithfullbandreflectionlessresponseandenhancedupperstopbandsuppression