A Dual-Mode Bandpass Filter with Multiple Controllable Transmission-Zeros Using T-Shaped Stub-Loaded Resonators

A dual-mode broadband bandpass filter (BPF) with multiple controllable transmission-zeros using T-shaped stub-loaded resonators (TSSLRs) is presented. Due to the symmetrical plane, the odd-even-mode theory can be adopted to characterize the BPF. The proposed filter consists of a dual-mode TSSLR and two modified feed-lines, which introduce two capacitive and inductive source-load (S-L) couplings. Five controllable transmission zeros (TZs) can be achieved for the high selectivity and the wide stopband because of the tunable amount of coupling capacitance and inductance. The center frequency of the proposed BPF is 5.8 GHz, with a 3 dB fraction bandwidth of 8.9%. The measured insertion and return losses are 1.75 and 28.18 dB, respectively. A compact size and second harmonic frequency suppression can be obtained by the proposed BPF with S-L couplings.

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Compact dual-mode microstrip bandpass filter based on slotted square patch resonator

Microelectronics International ◽

10.1108/mi-08-2021-0080 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Karthie S. ◽

Zuvairiya Parveen J. ◽

Yogeshwari D. ◽

Venkadeshwari E.

Keyword(s):

Bandpass Filter ◽

Filter Design ◽

Center Frequency ◽

Dual Mode ◽

Content Type ◽

Transmission Zeros ◽

Compact Size ◽

Mode Response ◽

Better Than ◽

Good Agreement

Purpose The purpose of this paper is to present the design of a compact microstrip bandpass filter (BPF) in dual-mode configuration loaded with cross-loop and square ring slots on a square patch resonator for C-band applications. Design/methodology/approach In the proposed design, the dual-mode response for the filter is realized with two transmission zeros (TZs) by the insertion of a perturbation element at the diagonal corner of the square patch resonator with orthogonal feed lines. Such TZs at the edges of the passband result in better selectivity for the proposed BPF. Moreover, the cross-loop and square ring slots are etched on a square patch resonator to obtain a miniaturized BPF. Findings The proposed dual-mode microstrip filter fabricated in RT/duroid 6010 substrate using PCB technology has a measured minimum insertion loss of 1.8 dB and return loss better than 24.5 dB with a fractional bandwidth (FBW) of 6.9%. A compact size of 7.35 × 7.35 mm2 is achieved for the slotted patch resonator-based dual-mode BPF at the center frequency of 4.76 GHz. As compared with the conventional square patch resonator, a size reduction of 61% is achieved with the proposed slotted design. The feasibility of the filter design is confirmed by the good agreement between the measured and simulated responses. The performance of the proposed filter structure is compared with other dual-mode filter works. Originality/value In the proposed work, a compact dual-mode BPF is reported with slotted structures. The conventional square patch resonator is deployed with cross-loop and square ring slots to design a dual-mode filter with a square perturbation element at its diagonal corner. The proposed filter exhibits compact size and favorable performance compared to other dual-mode filter works reported in literature. The aforementioned design of the dual-mode BPF at 4.76 GHz is suitable for applications in the lower part of the C-band.

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Design of Novel Compact Quad-Band Bandpass Filter with High Selectivity

Frequenz ◽

10.1515/freq-2019-0043 ◽

2020 ◽

Vol 74 (1-2) ◽

pp. 53-59

Author(s):

Qingchun Cao ◽

Hui Liu ◽

Li Gao

Keyword(s):

Return Loss ◽

High Selectivity ◽

Bandpass Filter ◽

Center Frequency ◽

Transmission Zeros ◽

Compact Size ◽

Left And Right ◽

Embedded Structure ◽

Better Than ◽

Good Agreement

AbstractThis paper presents a compact quad-band bandpass filter. The filter is realized by multi-embedded stub-load resonators. By utilizing multi-embedded structure, the whole filter exhibits a compact size. And due to the multi-section stub-loaded lines, four passbands can be realized and the center frequency of the four passbands can be controlled individually to accommodate different communication protocols. Moreover, by using 0° degree feed structure, there are two transmission zeros locates at left and right side of a passband, which greatly enhance the selectivity. To validate the proposed idea, a quad-band bandpass filter, which operates at 2/2.7/3.45/4.55 GHz is implemented. The insertion loss is smaller than 2 dB and return loss is better than 10 dB. Good agreement between the predicted and measured results demonstrates the proposed idea.

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Ultra-compact quasi-elliptic bandpass filter based on capacitive-loaded eighth-mode SIW cavities

International Journal of Microwave and Wireless Technologies ◽

10.1017/s175907871900120x ◽

2019 ◽

Vol 12 (2) ◽

pp. 109-115 ◽

Cited By ~ 1

Author(s):

Qing Liu ◽

Dongfang Zhou ◽

Dewei Zhang ◽

Chenge Bian ◽

Yi Zhang

Keyword(s):

Fourth Order ◽

High Selectivity ◽

Bandpass Filter ◽

Metal Layer ◽

Center Frequency ◽

Fractional Bandwidth ◽

Dielectric Substrates ◽

Transmission Zeros ◽

Compact Size ◽

Metal Layers

AbstractThis paper reports a novel fourth-order quasi-elliptic bandpass filter (BPF) based on capacitive-loaded eighth-mode substrate integrated waveguide (CLEMSIW) cavities. The CLEMSIW cavity is constructed by the conventional eighth-mode SIW with two dielectric substrates and three metal layers; a metal via is employed to connect the middle and bottom metal layers. The middle metal layer achieves a large loading capacitance to shift the resonance frequency. The proposed filter is designed in a quadruple scheme, and two controllable finite-transmission zeros can be realized. For the demonstration, a prototype with a center frequency of 1 GHz and a fractional bandwidth of 10% was designed, fabricated, and measured. The measured results agree well with simulated ones. The proposed filter has advantages of ultra-compact size, high selectivity, and good stopband performances.

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Miniaturized Wideband Bandpass Filter based on Capacitor-loaded One-eighth Wavelength Coupled Line

Applied Computational Electromagnetics Society ◽

10.47037/2021.aces.j.360707 ◽

2021 ◽

Vol 36 (7) ◽

pp. 865-871

Author(s):

Jin Shi ◽

Jiancheng Dong ◽

Kai Xu ◽

Lingyan Zhang

Keyword(s):

Insertion Loss ◽

Simple Structure ◽

Bandpass Filter ◽

State Of The Art ◽

Center Frequency ◽

Fractional Bandwidth ◽

Coupled Line ◽

Transmission Zeros ◽

Compact Size ◽

Multiple Transmission

A novel miniaturized wideband bandpass filter (BPF) using capacitor-loaded microstrip coupled line is proposed. The capacitors are loaded in parallel and series to the coupled line, which makes the filter just require one one-eighth wavelength coupled line and achieve filtering response with multiple transmission poles (TPs) and transmission zeros (TZs). Compared with the state-of-the-art microstrip wideband BPFs, the proposed filter has the advantages of compact size and simple structure. A prototype centered at 1.47 GHz with the 3-dB fractional bandwidth of 86.5% is demonstrated, which exhibits the compact size of 0.003λ2 g (λg is the guided wavelength at the center frequency) and the minimum insertion loss of 0.37 dB.

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Dual-mode resonator filter with improved feed-lines for dual-band applications

Journal of Electrical Engineering ◽

10.2478/jee-2020-0060 ◽

2020 ◽

Vol 71 (6) ◽

pp. 433-435

Author(s):

Shan Shan Gao ◽

Jia-Lin Li ◽

Zhe Lin Zhu ◽

Jia Li Xu ◽

Yong Xin Zhao

Keyword(s):

Simple Structure ◽

High Selectivity ◽

Bandpass Filter ◽

Dual Band ◽

Dual Mode ◽

Transmission Zeros ◽

Good Consistency ◽

Mode Resonator

AbstractAn improved feedline configuration for dual-mode resonator filter is investigated in this paper. Based on the introduced topology, a dual-mode dual-band bandpass filter with center frequencies of 1.8 and 2.4 GHz is optimally designed, fabricated and tested. The introduced dual-band bandpass filter has simple structure and enables high selectivity to be realized due to two pairs of transmission zeros located near to the lower and upper passband, respectively. Both measured and simulated performances are presented with good consistency.

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Compact dual mode X-band SIW bandpass filter with wide spurious suppression using split square ring slot resonator

Circuit World ◽

10.1108/cw-08-2019-0094 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Sandhya Ramalingam ◽

Umma Habiba Hyder Ali ◽

Sharmeela Chenniappan

Keyword(s):

Bandpass Filter ◽

Equivalent Circuit Model ◽

Circuit Board ◽

Center Frequency ◽

Design System ◽

Dual Mode ◽

Content Type ◽

X Band ◽

Compact Size ◽

Spurious Suppression

Purpose This paper aims to design a dual mode X-band substrate integrated waveguide (SIW) bandpass filter in the conventional SIW structure. A pair of back-to-back square and split ring resonator is introduced in the single-layer SIW bandpass filter. The various coupling configurations of SIW bandpass filter using split square ring slot resonator is designed to obtain dual resonant mode in the passband. It is shown that the measured results agree with the simulated results to meet compact size, lower the transmission coefficient, better reflection coefficient, sharp sideband rejection and minimal group delay. Design/methodology/approach A spurious suppression of wideband response is suppressed using an open stub in the transmission line. The width and length of the stub are tuned to suppress the wideband spurs in the stopband. The measured 3 dB bandwidth is from 8.76 to 14.24 GHz with a fractional bandwidth of 48.04% at a center frequency of 11.63 GHz, 12.59 GHz. The structure is analyzed using the equivalent circuit model, and the simulated analysis is based on an advanced design system software. Findings This paper discusses the characteristics of resonator below the waveguide cut-off frequency with their working principles and applications. Considering the difficulties in combining the resonators with a metallic waveguide, a new guided wave structure – the SIW is designed, which is synthesized on a planar substrate with linear periodic arrays of metallized via based on the printed circuit board. Originality/value This study has investigated the wave propagation problem of the SIW loaded by square ring slot-loaded resonator. The electric dipole nature of the resonator has been used to achieve a forward passband in a waveguide environment. The proposed filters have numerous advantages such as high-quality factor, low insertion loss, easy to integrate with the other planar circuits and, most importantly, compact size.

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Multilayer SIW Dual-Band Filters with Independent Band Characteristics and High Selectivity

Frequenz ◽

10.1515/freq-2019-0024 ◽

2019 ◽

Vol 73 (9-10) ◽

pp. 293-300

Author(s):

Dinghong Jia ◽

Jianqin Deng ◽

Yangping Zhao ◽

Ke Wu

Keyword(s):

High Selectivity ◽

Bandpass Filter ◽

Large Range ◽

Metal Layer ◽

Dual Band ◽

Effective Dimension ◽

Dual Mode ◽

Transmission Zeros ◽

Design Freedom ◽

Good Agreement

Abstract This work presents an approach to developing dual-mode dual-band substrate integrated waveguide (SIW) bandpass filter based on multilayer process. TE102/TE201 and TE101/TE102 modes are used to feature the two passbands, respectively. To begin with, large range of band location ratios are decided by the effective dimension of the SIW resonator. With reference to the field distribution, independent coupling schemes of the dual-modes are then realized by slots or circular apertures etched on the middle metal layer. It allows to not only introduce a large design freedom of bandwidth but also keep compactness. Finally, source-load and mixed couplings are deployed to produce transmission zeros around the passband in providing a sharp selectivity in the two filters, respectively. The details to independently control the center frequencies and bandwidth of two passbands are also presented. A two-order double-layered and a triple-layered SIW dual-band bandpass filter are prototyped to evaluate the proposed design approach, respectively. Results show a good agreement between simulations and measurements. The proposed filter exhibits flexible design freedom, high selectivity as well as good out-of-band rejection.

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A Novel Dual-Mode Microstrip Bandpass Filter with a Pair of Equal Crossed Slots

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.236-237.1383 ◽

2012 ◽

Vol 236-237 ◽

pp. 1383-1388

Author(s):

Su Ping Li ◽

Cheng Guo Chang ◽

Wei Wu

Keyword(s):

Insertion Loss ◽

Bandpass Filter ◽

Center Frequency ◽

Low Loss ◽

Dual Mode ◽

Transmission Zeros ◽

Filter Structure ◽

Relative Bandwidth

A novel dua1-mode microstrip bandpass filter with two triangle corner cuts and a pair of equal crossed slots is proposed. The performance of the designed filter is studied in detail. The proposed filter structure uses a single patch without coupling gaps. The center frequency is about 2.11GHz. The 3dB relative bandwidth is 9.95%, and the minimum insertion loss in the passband is 0.12dB. Two transmission zeros can be implemented on both sides of the passband. The insertion loss is l0dB within 2.04-2.18GHz. The effect on the filter’s performance by changing filter parameters is studied. The results show that this new filter can provide a low loss and make miniaturization easy.

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A Compact Quint-Band Bandpass Filter Based on Stub-Loaded Resonators

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.1208 ◽

2017 ◽

Vol 7 (3) ◽

pp. 1694-1698

Author(s):

M. Farhat ◽

J. Munisami ◽

M. Abdul-Niby ◽

M. Nahas

Keyword(s):

Design Methodology ◽

High Selectivity ◽

Bandpass Filter ◽

Center Frequency ◽

High Isolation ◽

The Third ◽

Transmission Zeros ◽

Band Filter ◽

Sufficient Degree ◽

Simulation Results

This paper presents a planar quant-band bandpass filter with a high out-of-band rejection. The filter is based on inter-coupled stub-loaded resonators, where pairs of resonators are electromagnetically coupled to each other and the feed lines. This results in excitation of passbands, where the first and the third passbands are generated by λ/4 stub-loaded resonators. The second and the fifth passbands are excited by λ/2 stub-loaded resonators. And the fourth passband is generated by λ/2 resonators. The proposed technique provides sufficient degree of freedom to control the center frequency and bandwidth of the five passbands. In addition, the seven transmission zeros created around the passbands results in a quant-band filter with high selectivity, sharp 3dB cut-off frequency, high isolation, and low passband insertion-loss. Design methodology and simulation results of the filter are provided.

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