Three-Pole Tunable Filters With Constant Bandwidth Using Mixed Combline and Split-Ring Resonators

Zhao, Zeyu; Jiang, Chen; Yang, Lin; Chen, Kunhe

doi:10.1109/lmwc.2014.2340996

Cited by 36 publications

(23 citation statements)

References 10 publications

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“…Q e value changes from 10.6 to 57 at 1.1 GHz when L 01 varies from 11 nH to 33 nH. Qe is unchanged with tuning frequency when L 01 is 11 nH, which satisfies the requirement of constant fractional bandwidth, as expressed in (12) [25] …”

Section: External Quality Factormentioning

confidence: 71%

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A Miniaturized Tunable Bandpass Filter With Constant Fractional Bandwidth

Cao¹,

Guangwen²,

Hu³

et al. 2015

PIER C

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Abstract-This paper presents a miniaturized tunable bandpass filter, consisting of two coaxial dielectric resonators and a pair of parallel-coupled lines. A coaxial dielectric resonators and a microstrip line form a new step-impedance resonator (SIR), which is different from a conventional SIR. Varactor diodes are connected to SIRs to tune the center frequency. The gap between parallel-coupled lines controls the inter-stage coupling coefficient. Lumped inductors used for coupling to I/O ports can reduce design complexity. The variations of coupling coefficient and external quality factor with tuning frequency are analyzed using HFSS software. A appropriate coupling coefficient which satisfies with constant fractional bandwidth within the tuning range is available. A tunable filter has been made of dielectric ceramics with dielectric constant of 38, fabricated on dielectric substrate and measured using Networks analyzer. Center frequencies vary from 0.43 GHz to 0.78 GHz, 3 dB fractional bandwidth from 6.4% to 6.8% when bias voltages are applied from 0 V to 10 V. The measured results validate the approach and agree with the simulation.

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Section: External Quality Factormentioning

confidence: 71%

“…Park and Rebeiz [11] designed low-loss tunable filters with three different fractional bandwidth variations including CFBW. Zhao et al [12] mixed combline and split-ring resonators to obtain tunable filter with CABW. El-Tanani and Rebeiz [13] proposed microstrip corrugated coupledline to maintain a nearly CABW across the tuning range.…”

Section: Introductionmentioning

confidence: 99%

A Miniaturized Tunable Bandpass Filter With Constant Fractional Bandwidth

Cao¹,

Guangwen²,

Hu³

et al. 2015

PIER C

View full text Add to dashboard Cite

show abstract

“…Large results in small and small results in large . In this design, the magnetic coupling is dominant and the total coupling strength can be expressed as (14) Meanwhile, the total coupling strength can be expressed as (15) where and denote the odd-and even-mode resonant frequencies.…”

Section: B Even-mode Analysismentioning

confidence: 99%

“…Recently, a tunable filter with constant absolute bandwidth has become a popular topic [13]- [16]. In [13]- [15], electric and magnetic coupling is utilized to make the coupling coefficient meet the requirement of constant absolute bandwidth. In [16], a microstrip corrugated coupled-line concept is used to realize constant absolute bandwidth.…”

Section: Introductionmentioning

confidence: 99%

Compact Tunable Filtering Power Divider With Constant Absolute Bandwidth

Gao

Zhang

Xue

2015

IEEE Trans. Microwave Theory Techn.

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This paper presents a novel frequency-agile filtering power divider with constant absolute bandwidth and high selectivity. The proposed design utilizes four coupled resonators to obtain the two functions of power division and filtering. Synthesis of the filtering power divider is carried out and the design guidelines are given. Varactors are then loaded to the resonators to enable frequency tuning. By using capacitors as well as magnetic and electric coupling to obtain required external quality factors and coupling coefficients, a constant absolute bandwidth is maintained when tuning the frequency. To demonstrate the validity of the proposed design, a circuit was fabricated. Experimental results show that the operating frequency can be changed from 0.62 to 0.85 GHz with the 3-dB absolute bandwidth of 60 2.5 MHz. Moreover, transmission zeros are generated near the passband, resulting in high selectivity for each tuning state. Comparisons between the measured and simulated results are presented and good agreement is observed.Index Terms-Bandpass response, constant absolute bandwidth, high selectivity, integration, tunable power divider.

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“…Open-ring resonator (ORR) is one of the modified forms of half wave-length uniform resonator and is widely used with good performance [25,26]. In this paper, DTC loaded ORRs are used to design a third order microstrip tunable filter.…”

Section: Introductionmentioning

confidence: 99%

A Uhf Third Order 5-Bit Digital Tunable Bandpass Filter Based on Mixed Coupled Open Ring Resonators

Fu¹,

Xiang²,

Zhang³

et al. 2016

PIER C

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Abstract-This paper presents a third-order digital tunable bandpass filter based on digitally tunable capacitor loaded microstrip open ring resonator. Magnetic dominated mixed coupling is utilized to make the coupling coefficient meet the requirement of stable bandwidth response. Electric source-load coupling is designed to generate a transmission zero for improving the frequency selectivity. This filter is designed, fabricated and measured. The measurement shows that the filter can be digitally tuned by 5-bits pure digital command. The fractional bandwidth is 9 ± 1%, and the tuning range is from 410 MHz to 820 MHz.

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Three-Pole Tunable Filters With Constant Bandwidth Using Mixed Combline and Split-Ring Resonators

Cited by 36 publications

References 10 publications

A Miniaturized Tunable Bandpass Filter With Constant Fractional Bandwidth

A Miniaturized Tunable Bandpass Filter With Constant Fractional Bandwidth

Compact Tunable Filtering Power Divider With Constant Absolute Bandwidth

A Uhf Third Order 5-Bit Digital Tunable Bandpass Filter Based on Mixed Coupled Open Ring Resonators

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