Compact Constant Bandwidth Tunable Wideband BPF With Second Harmonic Suppression

Kumar, Nagendra; Singh, Yaduvir

doi:10.1109/lmwc.2016.2615001

Cited by 14 publications

(11 citation statements)

References 7 publications

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“…Two methods are always used to achieve CABW or CFBW. The first way is to control the coupling strength by using varactors or selecting a proper coupling region [3][4][5][6][7]. The other method is to control the distance between the in-band transmission poles [8,9].…”

Section: Introductionmentioning

confidence: 99%

An Intrinsically Switched Tunable CABW/CFBW Bandpass Filter

Bo-ran

Zhang

et al. 2021

Electronics

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In this paper, a novel intrinsically switched tunable bandpass filter based on a dual-mode T-shaped varactor-loaded resonator is presented. The varactors loaded in the T-shaped resonator are capable of efficiently tuning the resonant frequencies of the even and odd modes, as well as the transmission-zero frequency. Without any additional RF switches, the passband of the filter can be intrinsically switched off by adjusting the transmission zero to the resonant frequencies. In the switch-on state, the constant absolute bandwidth (CABW) or constant fractional bandwidth (CFBW) passband can be achieved by controlling the frequency space between the two resonances. For a demonstration, a 0.8–1.1 GHz intrinsically switched tunable bandpass filter with 74 MHz CABW or 8.5% CFBW was fabricated and tested. In the whole operating band with |S11| < 10 dB, the insertion losses for CABW and CFBW are better than 3.3 dB and 3 dB, respectively, and the isolations are better than 20 dB in the switch-off state. The measured results have a good agreement with simulated results, which verifies the design theory.

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Section: Introductionmentioning

confidence: 99%

An Intrinsically Switched Tunable CABW/CFBW Bandpass Filter

Bo-ran

Zhang

et al. 2021

Electronics

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“…The coupling structure in this article was different from the conventional tunable coupling structure. [12][13][14][15][16][17][18][19][20] The coupling coefficient between the resonators in this article was adjusted by changing the electromagnetic field distribution on the resonators. The coupling strength between resonators can be adjusted by adjusting the value ratio of the capacitor between the two ends.…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15][16] The varactors were widely used to adjust the performance of the tunable filters. [17][18][19][20] In the design method mentioned above, the tunable broadband BPF has a compact size. But owing to the special resonator structures, it was difficult for these tunable BPF to be designed easily to meet other requirements.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In order to meet the application requirements in different electromagnetic environments in different places and times, the demand for the tunable broadband BPF with the center frequency and bandwidth can also be adjusted according to actual requirements was proposed. [12][13][14][15][16][17][18][19][20] In documents available, the tunable broadband BPF was mainly consisted of special resonator structures such as the tunable BPF based on liquid-crystal. [12][13][14] The PIN diodes were usually adopted as a tune method to switch the statues of the resonators and coupling structures.…”

Section: Introductionmentioning

confidence: 99%

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A tunable broadband bandpass filter based on quarter wavelength resonators

Zhao¹,

Zhang

2021

Int J RF Mic Comp-Aid Eng

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In this letter, a tunable broadband bandpass filter (BPF) based on quarter wavelength resonators was proposed. The resonators and coupling structures were mainly consisted of quarter wavelength transmission lines and tunable devices loaded at the two ends of the transmission lines. The resonant frequency of the BPF can be adjusted through changing the total capacitance at the both ends of the resonators. Especially, the coupling strength between resonators can be adjusted by adjusting the value ratio of the capacitor between the two ends. The tunable BPF in this scheme had the advantages of simply design. The bandwidth and center frequency of the tunable BPF can be tuned independently at the same time. As a demonstrator, an eight-orders filter was designed and fabricated on Rogers3006 substrate. The center frequency can be tuned in the range of 0.81 to 1.28 GHz, the relative tuning range was 45%. The relative bandwidth of the tunable filter can be tuned in the range of 14% to 38%. The simulated results were agreement well with the measured ones.

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“…By suitably locating three pairs of varactor diodes in the short-circuited coupled lines, the central frequency, bandwidth, and TZ of the BPF could be efficiently controlled. In [12], a CABW tunable microstripBPF consisting of two varactor-loaded nonuniform quarter-wave spiral resonators was investigated. The tunable selectivity and tunable passband were achieved by controlling the inherent TZs, which were generated by a combline coupled section.…”

Section: Introductionmentioning

confidence: 99%

Design of a Microstrip Three-State Switchable and Fully Tunable Bandpass Filter With an Extra-Wide Frequency Tuning Range

Chen

2020

IEEE Access

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In this study, a new method and structure are proposed to design of a switchable and fully tunable microstrip bandpass filter (BPF). The central frequency and bandwidth (or the resonance frequency of the resonators, coupling coefficient between resonators, and external quality factor of the I/O resonator) of the proposed BPF can be efficiently controlled using varactor diodes as tuners. In addition, the proposed BPF is designed to have three operating states, each with a different frequency tuning range. The three operating states can be switched between independently by introducing three pairs of switching diodes in the input and output feeding structures. Because of the ability to switch among the three operating states, an extra-wide frequency tuning range can be achieved. For demonstration, a two-pole switchable and tunable BPF was designed and implemented using microstrip technology. The experimental and simulation results were consistent and indicate that a wide frequency tuning range from 0.54 to 2.4 GHz, corresponding to a fractional tuning range of 127%, and a nearly constant absolute bandwidth of 82 MHz are achieved. In addition, the proposed switchable and tunable BPF is small (0.24λ g × 0.15λ g ).INDEX TERMS Bandpass filter (BPF), microstrip filter, switchable filter, tunable filter.

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Compact Constant Bandwidth Tunable Wideband BPF With Second Harmonic Suppression

Cited by 14 publications

References 7 publications

An Intrinsically Switched Tunable CABW/CFBW Bandpass Filter

An Intrinsically Switched Tunable CABW/CFBW Bandpass Filter

A tunable broadband bandpass filter based on quarter wavelength resonators

Design of a Microstrip Three-State Switchable and Fully Tunable Bandpass Filter With an Extra-Wide Frequency Tuning Range

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