Independently Controllable Dual-Band Bandpass Filters Using Asymmetric Stepped-Impedance Resonators

Kim, Chan Ho; Chang, Kai

doi:10.1109/tmtt.2011.2168973

Cited by 82 publications

(66 citation statements)

References 18 publications

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“…The upper passband is constructed by two electrically-coupled asymmetrical SIRs and two magnetically-coupled quarter-wavelength resonators . The resonant frequency of the SIRs can be designed by controlling various combinations of characteristic impedance ratios and electrical length ratios [9]. Their coupling strength can be controlled by adjusting the gap width and length .…”

Section: Design Of the Fourth-order Dual-band Filtermentioning

confidence: 99%

“…Althought the independent inter-resonator coupling was achieved in [6], [7], the external coupling remained dependent. For a simultaneous independent external and inter-resonator coupling, in [8], [9], the so-called combination structure was used, that is to combine two single-band filters with different center frequency. But they Manuscript often suffer from a large circuit size.…”

Section: Introductionmentioning

confidence: 99%

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Design of a Fourth-Order Dual-Band Bandpass Filter With Independently Controlled External and Inter-Resonator Coupling

Yan

Cao

et al. 2015

IEEE Microw. Wireless Compon. Lett.

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A microstrip filter structure suitable for implementation of multi-order dual-band bandpass filter is presented. Two passbands have separate signal paths and the structures are assembled together novelly. The independently controlled external and inter-resonator coupling can be simultaneously achieved. The design is based on the conventional filter design method. To take account of the effect between two passbands, the extraction of the external quality factor in one passband considers the effect of the other passbands and the direct source-load coupling introduced by the upper band structure is equivalent to an impedance inverter in the lower passband. As an example, a fourth-order dual-band filter for WLAN applications is designed and fabricated. The measured results have a good agreement with the simulated ones, which verifies effectiveness of the design.Index Terms-Bandpass filter (BPF), dual-passband, multiorder, multipath, stepped impedance resonator (SIR).

show abstract

Section: Design Of the Fourth-order Dual-band Filtermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design of a Fourth-Order Dual-Band Bandpass Filter With Independently Controlled External and Inter-Resonator Coupling

Yan

Cao

et al. 2015

IEEE Microw. Wireless Compon. Lett.

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show abstract

“…The TZ 3 and TZ 4 are produced by the hook-shape feed lines. Among them, TZ 3 is created due to the total length of hook-shape lines being λ/4 at this frequency and TZ 4 is created by the coupling between the feed lines and the resonator [20]. The measurement was performed on an Agilent 8719ES network analyzer.…”

Section: Filter Design Fabrication and Measurementmentioning

confidence: 99%

Dual-Band Bandpass Filter With Wide Upper Stopband Using Novel Stepped Impedance Stub-Loaded Quad-Mode Resonator

Lin¹,

Zhang²,

Sun³

et al. 2015

PIER Letters

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Abstract-This paper presents a wide upper stopband dual-band bandpass filter (BPF) with controllable passband frequencies and bandwidths as well as a high out-of-band rejection level. The proposed filter is realized by utilizing a novel stepped impedance stub-loaded quad-mode resonator. All the four-mode equivalent circuits of the resonator are quarter-wavelength stepped impedance resonators (SIRs), and their fundamental resonance frequencies are used to form the passbands, so the designed filter has a compact circuit size. By controlling the impedance and length ratios of the stubs of the resonator, wide upper stopband performance is obtained. Hook-shape feed-lines and source-load coupling are applied to provide appropriate external coupling and generate three extra transmission zeros, which greatly improve the selectivity of the proposed filter. An experimental filter operating at 1.5 and 3.5 GHz is designed, fabricated, and measured for validation. The measured results have good agreement with the simulated ones.

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“…For f odd lower than f even , the transmission zero T z5 can be generated by Resonator III. As explained in [12,13], the transmission zeros T z2 and T z6 can be generated by the long feed lines. The transmission zeros T z3 and T z8 can be generated by the coupling between two transmission lines of Resonator I.…”

Section: Compact Dual-mode Tri-band Microstrip Bpfmentioning

confidence: 99%

Compact Dual-Mode Tri-Band Microstrip BPF With Three Sets of Resonators

Zhou¹,

Zhao²,

Fu³

et al. 2012

PIER Letters

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Abstract-In this letter, a novel compact dual-mode tri-band microstrip bandpass filter (BPF) is proposed using three sets of dualmode resonators, i.e., the quarter-wavelength resonator (QWR) which is designed for the first passband, and two sets of stub loaded resonators (SLR) for the second and third passband, respectively. The center frequencies and bandwidths of three passbands can be flexibly tuned and designed. Multiple transmission zeros can be generated to improve the selectivity. Meanwhile, the BPF can obtain more compact size by adopting the folded resonators and extended feed lines. Finally, a triband microstrip BPF prototype with fractional bandwidths 18.3% at 1.8 GHz, 5.5% at 3.6 GHz and 12.2% at 5.25 GHz is designed. The measured results are in good agreement with the full-wave simulation results.

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Independently Controllable Dual-Band Bandpass Filters Using Asymmetric Stepped-Impedance Resonators

Cited by 82 publications

References 18 publications

Design of a Fourth-Order Dual-Band Bandpass Filter With Independently Controlled External and Inter-Resonator Coupling

Design of a Fourth-Order Dual-Band Bandpass Filter With Independently Controlled External and Inter-Resonator Coupling

Dual-Band Bandpass Filter With Wide Upper Stopband Using Novel Stepped Impedance Stub-Loaded Quad-Mode Resonator

Compact Dual-Mode Tri-Band Microstrip BPF With Three Sets of Resonators

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